[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.

None of this is any longer required now that we aren't auto-updating the submodules.  These are all routines only called by the `update_submodules_and_commit_shas_if_detached_head` function at the bottom.