instance-kvm-export.cfg were copying parts defined in instance-kvm.cfg, but as
the latter one was evolving a lot, it was missing features.

For simplicity let instance-kvm.cfg expose the parts in a way, that
instance-kvm-export.cfg can blindly append the to list of own parts, as it has
to support resiliency exporter by itself.

Now that we updated postfix, we can use default openssl

According to http://www.postfix.org/announcements/postfix-3.1.2.html

> Fixed with Postfix 3.1.2:
> Changes to make Postfix build with OpenSSL 1.1.0.

Going Go1.15.10 -> Go1.15.11 brings in fixes to compiler, runtime and stdlib:

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 Go1.16.2 -> Go1.16.3 brings in fixes to compiler, runtime and stdlib:

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

Tested on helloworld SR.

See merge request nexedi/slapos!940

Gcc fails to recognize hard-float kernel on Olimex-Lime2 board.

For that reason gcc is automatically compiled using soft-float
convention and causes a failure.

The only purpose of Apache is to protect the registry process
from public internet, because we don't trust Python2 HTTP layer.

The re6st registry is designed to work with plain HTTP
because it does authentication & encryption internally.

This repository from the source of the pull request was removed, let's use a
local copy for now.

also:
 - install logcli for convenience / debugging
 - no longer set golang version here, now that 1.16 is the default

Before this commit buildout could fail when instantiating Theia after
updating to a new software release because it tried to create already
existing symbolic links. These symlinks were to let the backend Caddy
serve the logo and fonts.

This commit solves the issue by systematically overwriting existing
files when creating the symlinks, and also directly copies the logo.

adjust to changes in kvm software release and erp5.util

Apps where downloaded during "slapos node instance" step, which has several
problems:
 - first, instance step is not supposed to require network access
 - this was downloading "latest" version of the app, which made the software
   not reproductible
 - since a few weeks this was no longer working, as we could see in test results

This is unused obsolete feature, which results with users being tricked to
configure VMs wrongly.

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 0fbed0d1b (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.