Cleanup old versions on 2018-patches

Resolves #48 (closed) by removing unneeded directories in the StrippingArchive, StrippingSettings, and CommonParticleArchive.

I chose to leave the previous incremental restrips of 2016 and 2018, and the previous 2018 restrips of Pb-Pb and Pb-Ne in case some want to pull inspiration from these.

Any other versions may be accessed again by checking out previous commits.