Version numbering updates

#207 (closed) suggests adding version numbers to renders, and also giving version numbers instead of hashes for beta builds.

This draft MR is an attempt to do that. (appears to work...)

• Change version tag to accept full versions, Release candidates and Betas (not alpha and not other tags)
• Add unit test for tag version. Run the test in the lint_build_system job.
• Add tag to main body in renders, but do not add commit hash for untagged builds

Note added by Julian:

There is a really weird problem with GitLFS and Gitlab, where when we run in CI git reports that some (not all) LFS object have been changed. To get the correct version string we need to run git reset --hard. It appears that running git rest --hard creates some empty STLs which causes the renders to fail. As such we cannot run git reset --hard for the render job.

If we disable the version string calculation for untagged builds then we never check the git status. This means that we will only know about pipeline stability when we try to release. As such, the only way we can be sure that the pipeline is stable is to run the full version string check every time. The hashes may look ugly in the renders, but they keep the CI job as close as possible to the release job.

We still need to find a solution to the git rest issue. Which may need to be calculating the version string in a different job

closes: #207 (closed)