Install setuptools_scm before python-dateutil (which has it in setup_requires) so that the version can be controlled by buildout

See nexedi/slapos@f1e7230e

Haproxy log errors for events like when all backends from a family fail the
health check, it is helpful for investigations to have a timestamp in this log.

We were using ActionFileDefaultTemplate so that access logs use standard
"combined"-like format, we change so that this apply only to the access log,
so that error log have the default "timestamp hostname process[pid] message"
format.

be6c35c (manager/getAllowedExtensionList: use explicit extensions in ERP5 legacy mode, 2021-03-29)
fixes issues with compatibility with ERP5

Porting to switch-softwaretype involves:
 - use recipe slapos.cookbook:switch-softwaretype instead of slapos.cookbook:softwaretype
 - don't render software type profiles, only use cloudooo-dynamic-template:rendered
  instead of ${cloudooo-dynamic-template:rendered}, the profile will be rendered
  later.
 - have a RootSoftwareInstance default alias
 - have a part reading parameters using slapos.cookbook:slapconfiguration
  named slap-configuration. This is what slapos.cookbook:switch-softwaretype
  expects. Here we renamed the existing part.

At the same time, remove slap-connection that was added as backward compatibility,
slapos.core supports this since commit 0fbed0d1 (Migrate slap_connection to
 slap-connection, and use variables names separated with '-'., 2012-09-18) that
was part of release 0.29

These profiles assumed that bzip is in PATH but it's no longer the case with
default slapos install on debian 10.8

previous version is no longer installable causing all tests to fail
in a loop installing setuptools_scm for jsonschema, a problem which
was fixed in f1e7230e (cookbook: ensure working version of setuptools_scm, 2020-05-26)

en_US.UTF-8 might not be installed and in such case postgres refuses to start.

--disable-static is temporarilly removed due to build error
with xml2-config that does not support '--dynamic' argument.

slapos.cookbook recipe tests sometimes manipulate buildout eggs working set,
which will install packages from pypi. makeRecipe utilty function was
guessing buildout egg folders by parsing builout.cfg, but since a33844a2
(slapos-testing, slapos-sr-testing: Don't duplicate instance.cfg prologue
that is already provided by stack/nxdtest/instance.cfg, 2021-03-22),
these are defined in an extended profile, so this stopped working.

Instead of this fragile pattern, make the test software release pass the eggs
directories with an explicit environment variable.

See merge request nexedi/slapos!951

The golang.go extension can overwrite the shell environment PATH,
which can break the shell.

1.0.154 can not be installed anymore because buildout tries to install
setup_requires packages to their latest version

When system GCC is too old, SlapOS GCC may produce binaries
that 'strip' does not process correctly.

The _vh_ prefix is needed for every single outer path element for
VirtualHostMonster to be able to properly reconstruct the outer path.

Also remove old golang 1.13 version

This Go release is EOL now.

Don't drop support for Go1.12 and Go1.13 yet. Even though those Go releases are
also EOL since long ago, they are still being used inside SlapOS:

Go1.12 - by gitlab  (/cc @jerome, @alain.takoudjou)
Go1.13 - by galène  (/cc @tomo, @alain.takoudjou)

Component should not change a global setting like Go/Python/GCC version.
Only leaf software-releases can.

Going Go1.15.8 -> Go1.15.10 brings in fixes to compiler, runtime and stdlib
including security fixes to archive/zip and encoding/xml:

https://golang.org/doc/devel/release.html#go1.15.minor

Tested on helloworld SR (by adjusting it to use go1.15 instead of go1.16).

Going Go1.16 -> Go1.16.2 brings in fixes to compiler, runtime and stdlib
including security fixes to archive/zip and encoding/xml:

https://golang.org/doc/devel/release.html#go1.16.minor

Tested on helloworld SR.

See merge request !938