Remove dangling publish jobs and allow specifying of dist location

Most of our CI pipeline jobs only run on branches, rather than on MRs.

Update the pypi release job to take this approach, which means that we do not get dangling jobs to publish to pipy as part of an MR pipeline, even though the build may have failed on the branch pipeline created from the same commit.

Additionally allow the distribution location to be specified by CI variables, which allows us to make use of a distribution generated in an upstream job rather than building it within the publish job. This is useful for uis/devops/iam/identity-lib!9 (merged).

Close #33 (closed)