builder: `cleanup` command should clean outdated installer cache

[marmarek]

The problem you're addressing (if any)

Repeatedly building ISO uses a lot of disk space, and qb cleanup all doesn't help.

The solution you'd like

Cleanup action should also include cleaning up:

• old init-cache artifacts of installer
• old templates in installer cache (but leave most recent for each template name)

And maybe also cached templates no longer listed in the config? That would be old fedora versions in practice.

The value to a user and who that user might be

Less disk space needed for builder.

Completion criteria checklist

No response