This will deprecate the use of the highpriority image.

Refs. swh/infra/sysadm-environment#4881

This is also needed for loader svn in those workers.

Refs. swh/infra/sysadm-environment#4792

Related to https://gitlab.softwareheritage.org/infra/sysadm-environment/-/issues/4698

Ref. infra/sysadm-environment#4670

Ref. infra/sysadm-environment#4670

Related to infra/sysadm-environment#4659

Related to infra/sysadm-environment#4605

Related to infra/sysadm-environment#4605

This also fixes a typo in the Dockerfile.

Related to T4540

This allows to:
- drop the current swh-environment/docker image (which contains way too
much packages).
- fix the current issue since the init-container got installed in the swh charts for
loaders (as this expects an entrypoint.sh which is not present in the old image).

Related to T4144