to save disk space

See merge request !929

For now it's used only in repman, but instead of compiling from source it was
using a pre-build binary for linux64. This change to compile from source.

See merge request !933

The version >=5 is not python2 compatible.

instead of downloading a pre-binary that might not match the architecture

We still need to checkout from git these packages, because most
of them use `replace` in their go.mod, which is only compatible
with installing as main module, but not as an external module.

promtail will use go-systemd when cgo is enabled, but we don't
want to ship a full systemd in slapos, so we build with CGO_ENABLED=0

grafana on the other hand needs to be build with CGO_ENABLED, because
it will use sqlite3. grafana also needs to use yarn to build the
frontend, so it remain a dedicated section with ad-hoc installation
method.

Run this whole script in `set -e` so that if any of the go install
fail buildout exit with error.

With this new environment option to gowork section, it is possible
to specify environment variables that will be set during the build,
more specifically when env.sh is sourced.

The implementation is a bit complex, so that the syntax is not strict
and whitespace are tolerated in the definition, ie. all these should be
understood:

    [gowork]
    environment =
      A=a
      B =b
      C= c
      D=d=d

json-schemas test is complaining that some jsons are not formatted according to
this standard.

to make management of this template easier

       Partially updated from original instance-erp5.cfg.in file.

Xavier Thompson reports that when Theia is compiled inside Theia, Go
fails to install with the error showing that golang14's make.bash calls
`go install` to install cmd/go and other commands to the outer
go.work/bin instead of inside $GOROOT_FINAL set by the build recipe.

Similarly to nexedi/slapos!928 this
might be to the fact that internal `go install` prioritizes $GOBIN even
in the presence of set $GOROOT_FINAL.

-> Don't try to fix Go itself, and make the compilation more robust by
unsetting $GOBIN, so that even if that variable is set in the
environment where buildout runs, it does not affect the compilation
procedure.

Fixes: 8eac67a5 (golang: Prepare for future GOPATH removal)
Reported-on: https://www.erp5.com/group_section/forum/Go-compilation-error-P6f5WisQkc
Tested-by: @xavier_thompson
Reviewed-on: nexedi/slapos!932

   Partially updated from original instance-erp5.cfg.in file.

Introduces devperm manager with lsblk.

Use json to generate .slapos-disk-permission in a way, that devperm manager
will be able to consume it.

   Partially updated from original instance-erp5.cfg.in file

Use-case: when an host enry is used to define the outgoing binding IP of
zopes in a partition, this IP is host-dependent.

So that it proagates root instance's "balancer" parameter, as other
request-* sections do. No functional change is expected, this is rather
for code simplification and factorisation.

use this new mechanism, which avoids this parameter being misused
(inconsistent between partitions of the same family).
Preserve backward compatibility, giving precedence to the new mechanism.

Call them deadlines, as this is what they really are, but the "wrong" name
stuck on ERP5 side (for now).
Also, introduce a per-family-override mechanism, to avoid having per-
option equivalents for such mechanism.

Also, stop poping it: nothing else seems to be accessing the containing
dict, so mutating it does not seem necessary.

gitaly's Makefile forcibly sets $GOPATH to install in _build
folder. Once gitaly is built, it is expected to be in _build/bin/gitaly
and copied from there.

With 8eac67a5 (golang: Prepare for future GOPATH removal, 2021-02-26) the
env.sh sets GOBIN, to its own $GOPATH/bin

Since gitaly's build does not set $GOBIN, even if it overrides $GOPATH, the
final bin/gitaly is not in $GOPATH/bin/gitaly (with $GOPATH from Makefile),
but in $GOBIN/gitaly (with $GOBIN from env.sh)

To prevent this, unset $GOBIN before running make, which keeps the old
behavior of only using the $GOPATH from the Makefile

Update grafana, to use more recent golang. This also brings support of multi line logs in loki.

See merge request nexedi/slapos!921

See merge request nexedi/slapos!925

When the outside world path does not match the Zope path (typically: Web
Site).

By adding failover url the user is able to configure special backend to use
in case if the real backend is down.

Original PoC was done by Kazuhiko SHIOZAKI <kazuhiko@nexedi.com>.