RFE: command line utility to test patching

[NeilHanlon]

As a user, I want to be able to test a patch repository locally to develop new patches and/or iterate on existing ones in the case of failure.

Currently, the only CLI tool available to perform this work is srpmproc, which has different expectations than mothership does for the location and format of patch repositories, leading to both pre and post-processing required to transform an OpenELA-style patch repo into a Rocky-style (srpmproc) repo to work with, before then transforming the repo back into an OpenELA-style patch repo.

Ideally, as noted in #20, we should unify srpmproc and openela-style patches under srpmproc for OpenPatch 1.0; which may not be backwards compatible with the current srpmproc DSL.

[mstg]

I started on something in #28, currently it's only for unpacking and creating a patch "base". Where it unpack SRPM + tarball and you can make changes and create patches using git. We would expand on this to add local patch testing support + auto patch generation.