Thanks to work on TrafficServer bug 7425 it was possible to understand
correctly the switches and setup ATS to SlapOS CDN needs.

max_stale_age with negative_revalidating_enabled is used to simulate
stale-if-error and negative_revalidating_lifetime is set to 0, as Expires
header provided by this switch is needless in SlapOS case.

Tests are updated to follow the real use case, by rewriting ATS configuration
to meet times required for the test to finish in reasonable time.

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 nexedi/slapos!873

See merge request nexedi/slapos!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 nexedi/slapos!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 nexedi/slapos!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 nexedi/slapos!878

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

See merge request nexedi/slapos!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