[Finishes #80253548] Merge back to using one version of roboconf

# DO NOT MERGE (yet)

@JamesLavin and I are using this primarily to communicate at this time; make sure we both see things the same way.

Assumptions for this PR from [Pivotal story](https://www.pivotaltracker.com/story/show/80253548):

Main requirements changes:

1.  No longer offer auto-update since this will be handled by the submodule developers.  I.e. if they update a submodule, then they are responsible for updating the relevant parent project SHAs.  This carries over even into Jenkins deployments, since Jenkins cannot assume submodule SHA configuration.
1.  No presumption of only `master` branch for submodules; submodules can have their own branches.

Due to primarily the removal of auto-update, many bash functions are no longer required.

I will be testing using the file in this pull request.

Here's the crux: if `update_submodules_and_commit_shas` is still needed.  That is predicated on it ultimately invoking `update_git_submodules` which is only needed if you have the `--remote` flag to pull latest version on the submodules.  If that's no longer policy, then none of this is needed; hence all the functions being deleted.