docker: Libervia revision can now be specified: 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 directory and subdirectories contain files to build and manage Docker images of Salut à Toi.

Please refer to documentation for details.