Remove buildbot, buildbot-slave, and their orphaned dependencies

[icp1994]

The buildbot package hasn't been updated since almost six years. I don't think this is worth updating as it's safe to assume no one is actively using it from the void repo at v0.8.14 while upstream is at v3.5.0.

In reference to #38229 this also removes three of the subsequently orphaned packages: python-Jinja2, python-Twisted, and Twisted. Ideally we would remove python-dateutil and python-sqlalchemy-migrate but those provides their python3 counterparts as subpackages.

[paper42]

this buildbot package is used on our builders, we can't remove it until we have a better solution

[classabbyamp]

Ideally we would remove python-dateutil and python-sqlalchemy-migrate but those provides their python3 counterparts as subpackages.

when it comes time to remove those, they can be converted to a purely-python3 template.

There's also more orphaned dependencies in that dependency tree, especially the twisted part.