Docker build & run streamlining

[guillheu]

Checklist

• My branch is up-to-date with upstream/develop branch.
• Everything works and tested for Python 3.8.0 and above.
• I ran pre-commit checks against my changes.
• I've written tests against my changes and all the current present tests are passing.

Current behaviour

The overall build and run pipelines are a mess, both for this and the snapshotter. projects.json file being created and populated at run time is a hacky way to merge configuration sources. Similarily, the docker image does not have a default entrypoint, but does expect a very specific command in order to run at all, which is instead defined in the docker-compose.yaml manifest under the command service fields.

New expected behaviour

This is a small PR that aims to make the docker image a little easier to work with outside of the provided docker-compose from the snapshotter repo.

Change logs

• The creation of config/settings.json is now in the Dockerfile instead of the snapshotter_autofill.sh script, which shouldn't break the overall command chain but would make it possible for someone to mount a custom settings.json file at runtime and is overall better practice since that settings file is simply a default that is common to all container images
• Renaming init_processes.sh to docker-entrypoint.sh, which is a standard name easier to work with from the outside
• Wrapping the execution of snapshotter_autofill.sh inside of the newly renamed docker-entrypoint.sh, again making it easier to work with the container outside of the provided docker-compose
• Adding an ENTRYPOINT to the Dockerfile to ensure correct default behavior

[guillheu]

This is a joint PR with the snapshotter. That PR contains the changes to the docker-compose command.