Added test-install subcommand to inquisitor

test-install can be used to automate testing all valid package configurations.

Currently only tests one profile, and while it would be useful to test multiple, it will probably just be unnecessary work (e.g. openmw, where the current profile options are to do with the available DLC. On the other hand it would be useful if we introduced a BSA-based VFS, or eventually a zip-based one, as a separate profile, which would significantly change how installation works).