When connecting to Docker service, first the `backend` container will be tried with TCP,
then an Unix Socket will be used as fallback.
The Unix Socket is put in Libervia local dir which is a volume shared between containers.
This way D-Bus can be used with a remote backend, or the backend can be run locally
(notably during build when accounts creation or other settings must be done via Libervia
CLI).
Using the `DOCKER_LIBERVIA_REV` environment variable, backend (and related repos) revision
can now be specified. By default (variable empty or not set), the current `tip` version is
used, and `dev` is used for tagging. If the variable is set, the revision will be used and
used for tagging the image.
this will avoid a build each time the container starts fresh (notably with tests), as this
is time and resource consuming (notably with node modules which would need to be
downloaded each time).
`SAT_TEST_ENV_E2E` is set to `1` to indicate that e2e environment requirement are
available (notably specific accounts and hosts created). The e2e tests needing it won't be
launched if this variable is not set.
A network alias is set for the backend at `sat.test` (to have a tld available, needed for
some network libraries like OpenSSL).
This patch introduce new docker images, replacing the unmaintained ones which were in
sat_docs.
Images + docker-compose files are provided to use SàT backend and Libervia, but also to
integrate and configure Prosody and SàT PubSub to run end-to-end tests.
