Update to 1.9.0 ( https://github.com/eclipse-theia/theia/blob/v1.9.0/CHANGELOG.md#v190---16122020 )

Update extensions to newer version and to the URLs from openvsx instead of
github, since openvsx prevent maintainers to modify releases.

Also use buildout directly to download extensions, so that we verify signatures and have possibility to use cache

See merge request !873

See merge request !886

In reality, proxy.config.http.cache.max_stale_age was used for stale cache lifetime in current ATS implementation.
Thus we increase proxy.config.http.negative_revalidating_lifetime value to the same value as proxy.config.http.cache.max_stale_age whose default is 604800.

https://github.com/apache/trafficserver/issues/7417#issuecomment-757866872

See merge request !887

We want the tests to use the code from the repository, but when we have a
pinned version, buildout will use the code from repository only when the
version from the repository match the version spec from the pin.

The way slapos.recipe.template was pinned to 4.4 caused issues when we made
a change in slapos.recipe.template to make it 4.5, because tests were no
longer using code from slapos.recipe.template repository, but from 4.4 egg
from pypi.

To prevent this kind of issues, unset the slapos.recipe.template = 4.4
version pin and also unset the version for all tested egg, to prevent
similar issues if extended profiles also have version pins.

See merge request !876

This reverts commit 2f461da8.

Since Galene is behind our frontend, no need to take care of the HTTPS certificates.

See merge request !880

This also pulls in crawshaw.io/sqlite because it is used by lonet.

Due to unknown yet reason ATS and Caddy are loosing connections to haproxy,
which results with increased amount of 5xx (about 0.5% more cases).

No known solution was found yet on haproxy side, but this kind of workaround
stabilises frontend and definitely drops amount of in-frontend 5xx. The
observed situation with this workaround is no more 5xx sourcing in frontend
itself.

See merge request !878

See https://galene.org
Use first official version (0.1)
Co-authored-by: Thomas Gambier <thomas.gambier@nexedi.com>

See merge request !868

use "latest" in generate_download_plugins_cfg.py, so that re-running this
script updates plugins to their latest versions.

slapos.recipe.build verifies signatures of downloaded files and can also use
buildout cache or download from shacache, which

This introduces a new download-plugins.cfg, containing the URLs of
extensions and their md5sum signatures. This profile is extended by
software.cfg and there's a section using slapos.recipe.build to actually
download extensions.

A generate_download_plugins_cfg.py python script is also included, to be
run by software release maintainers to update download-plugins.cfg using the
list of plugins included in generate_download_plugins_cfg.py

Introduce a new "software release upgrade test", which tests a scenario of keating
an ERP5 instance with an old version of software release and then update it to
current version.

To support this test and because we are using this technique for most of slapos
softwares nowadays, configure zopes to restart automatically when their
configuration change.

See merge request !875

Update extensions to newer version and to the URLs from openvsx instead of
github, since openvsx prevent maintainers to modify releases.

add vscode-references-view (
https://open-vsx.org/extension/ms-vscode/references-view ) it's installed
in default Theia and looks good.

Some java extensions were not on openvsx, they were removed or updated.
Newer java extension seem to associate .cfg as "properties" files, so force a
mapping to make them open as zc-buildout.

python was also updated, but not to latest version which does not work on
Theia.