This partially reverts commit 20fb7c58.

Unfortunately having trustable X-Forwarded for in case of SlapOS Master
is not so simple, and not needed for now, as the approach is a bit different
on that apache, thus let's revert for now.

The update of AddOutputFilterByType is kept.

And not globally inside slapuser $HOME (which is go builtin default).

`go env` output: before:

    (go.work) slapuser34@vifibcloud-rapidspace-hosting-007:~/srv/runner$ go env
    GO111MODULE=""
    GOARCH="amd64"
    GOBIN=""
    GOCACHE="/srv/slapgrid/slappart34/.cache/go-build"
    GOENV="/srv/slapgrid/slappart34/.config/go/env"
    GOEXE=""
    GOFLAGS=""
    GOHOSTARCH="amd64"
    GOHOSTOS="linux"
    GOINSECURE=""
    GONOPROXY=""
    GONOSUMDB=""
    GOOS="linux"
    GOPATH="/srv/slapgrid/slappart34/srv/runner/software/09b17891535725b7c44e64fb2e856ebe/go.work"
    GOPRIVATE=""
    GOPROXY="https://proxy.golang.org,direct"
    GOROOT="/srv/slapgrid/slappart34/srv/runner/shared/golang1.14/da4c5c8222d5573da4d0e547cfc1793e"
    GOSUMDB="sum.golang.org"
    GOTMPDIR=""
    GOTOOLDIR="/srv/slapgrid/slappart34/srv/runner/shared/golang1.14/da4c5c8222d5573da4d0e547cfc1793e/pkg/tool/linux_amd64"
    GCCGO="gccgo"
    AR="ar"
    CC="gcc"
    CXX="g++"
    CGO_ENABLED="1"
    GOMOD=""
    CGO_CFLAGS="-g -O2"
    CGO_CPPFLAGS=""
    CGO_CXXFLAGS="-g -O2"
    CGO_FFLAGS="-g -O2"
    CGO_LDFLAGS="-g -O2"
    PKG_CONFIG="pkg-config"
    GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build196479275=/tmp/go-build -gno-record-gcc-switches"

after:

    (go.work) slapuser34@vifibcloud-rapidspace-hosting-007:~/srv/runner$ go env
    GO111MODULE=""
    GOARCH="amd64"
    GOBIN=""
    GOCACHE="/srv/slapgrid/slappart34/srv/runner/software/09b17891535725b7c44e64fb2e856ebe/go.work/cache"
    GOENV="/srv/slapgrid/slappart34/srv/runner/software/09b17891535725b7c44e64fb2e856ebe/go.work/goenv"
    GOEXE=""
    GOFLAGS=""
    GOHOSTARCH="amd64"
    GOHOSTOS="linux"
    GOINSECURE=""
    GONOPROXY=""
    GONOSUMDB=""
    GOOS="linux"
    GOPATH="/srv/slapgrid/slappart34/srv/runner/software/09b17891535725b7c44e64fb2e856ebe/go.work"
    GOPRIVATE=""
    GOPROXY="https://proxy.golang.org,direct"
    GOROOT="/srv/slapgrid/slappart34/srv/runner/shared/golang1.14/da4c5c8222d5573da4d0e547cfc1793e"
    GOSUMDB="sum.golang.org"
    GOTMPDIR=""
    GOTOOLDIR="/srv/slapgrid/slappart34/srv/runner/shared/golang1.14/da4c5c8222d5573da4d0e547cfc1793e/pkg/tool/linux_amd64"
    GCCGO="gccgo"
    AR="ar"
    CC="gcc"
    CXX="g++"
    CGO_ENABLED="1"
    GOMOD=""
    CGO_CFLAGS="-g -O2"
    CGO_CPPFLAGS=""
    CGO_CXXFLAGS="-g -O2"
    CGO_FFLAGS="-g -O2"
    CGO_LDFLAGS="-g -O2"
    PKG_CONFIG="pkg-config"
    GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build233719895=/tmp/go-build -gno-record-gcc-switches"

i.e. we change $GOCACHE and $GOENV to be per-workspace:

    --- a/goenv.before
    +++ b/goenv.after
    @@ -1,8 +1,8 @@
     GO111MODULE=""
     GOARCH="amd64"
     GOBIN=""
    -GOCACHE="/srv/slapgrid/slappart34/.cache/go-build"
    -GOENV="/srv/slapgrid/slappart34/.config/go/env"
    +GOCACHE="/srv/slapgrid/slappart34/srv/runner/software/09b17891535725b7c44e64fb2e856ebe/go.work/cache"
    +GOENV="/srv/slapgrid/slappart34/srv/runner/software/09b17891535725b7c44e64fb2e856ebe/go.work/goenv"
     GOEXE=""
     GOFLAGS=""
     GOHOSTARCH="amd64"

Explanation:

- Starting from Go1.10 the go command maintains cache for built packages, test results, etc:

  https://golang.org/doc/go1.10#build

  while this cache tries to remember by which go version and in which
  environment a package was built, and reusing the cached entry only when it is
  indeed correct to do so, by keeping this cache in a shared place - not per go
  workspace - we expose it to interactions with other go installments, which,
  due to e.g. software bugs might misbehave.

  -> keeping the build cache inside go workspace makes things more safe.

- Starting from Go1.13 the go command allows to keep its configuration and environment inside a file:

  https://golang.org/doc/go1.13#go-env-w
  https://go.googlesource.com/proposal/+/master/design/30411-env.md

  The default location for such file is per-user, which can bring
  misinteraction among several go workspace installments and wrt system go
  installment.

  -> move this configuration file into inside go workspace.

/reviewed-by: TrustMe

These are old Go releases that were stopped being updated in 2018 - mid
2019:

https://golang.org/doc/devel/release.html#go1.9
https://golang.org/doc/devel/release.html#go1.10
https://golang.org/doc/devel/release.html#go1.11

and that are not used by any in-tree SR or component.

Don't drop Go1.12 and Go1.13 yet: they are too outdated and no longer
supported, but those Go releases are still in use by the following
slapos software:

Go1.12: Caddy, GitLab, Grafana
Go1.13: RepMan, Restic

The maintainers of those software are advised to upgrade to Go1.14 due
to at least recent security fixes in net/http package.

Go1.10 is outdated by today as it was last updated in Jan 2019:

	https://golang.org/doc/devel/release.html#go1.10

Go1.14 is current oldstable - i.e. it is still supported and mature.

As currently no in-tree SR or component use gowork's default, the switch
should not introduce any breakage.

Going Go1.14.3 -> Go1.14.9 brings in many compiler and runtime fixes,
including security fixes to package net/http:

https://golang.org/doc/devel/release.html#go1.14

Switch helloweb from go1.13 -> go1.14 to test.

Tested on helloworld SR.

Going Go1.13.9 -> Go1.13.15 brings in many compiler and runtime fixes,
including security fixes to package net/http:

https://golang.org/doc/devel/release.html#go1.13

Switch helloweb from go1.12 -> go1.13 to test.

Tested on helloworld SR.

Going Go1.12.9 -> Go1.12.17 brings many fixes including security fixes for
net/http package:

https://golang.org/doc/devel/release.html#go1.12

Tested on helloworld SR.

See merge request !808

By copy paste mistake wrong log files were configured for log rotation,
resulting with damaging logrotate for the whole partition.

See merge request nexedi/slapos!791

By using nginx it's possible to set it up to expose logs nicely with the
real frontend.

furl is used to rewrite URL from the frontend to add proper username and
password information.

Also use default OpenSSL version.

pyflaked

See merge request nexedi/slapos!807

By using virtio-scsi-pci it's possible to attach many CD-ROMs to be boot from.

Thanks to using to draft-06 schema oneOf the "Boot image" field provides a
list of images to select one to boot.