More flexible dockerfile and build dev containers on CI.

[JHopeCollins]

This PR replaces #4400 to merge into main instead of release.

Major changes:

• The Dockerfile now accepts build arguments for whether to build the main or release branches, or a versioned release, as well as additional PETSc configure arguments or apt packages.
• The CI will build dev Docker containers on each push to main or release branch. This will be useful for downstream packages to use in their CI. The new containers are only firedrake-vanilla on linux (no macOS builds), and have the tags dev-main or dev-release. Full IDs: firedrake-vanilla-{default,complex}:dev-{main,release}

[connorjward]

Very happy with this. Assuming the final tests work happy to merge.

[JHopeCollins]

Only test failure is unrelated.