📝 ROOT(appendix): Initialize appendix

This commit introduces an informal community appendix, to start defining the unique etymology and jargon of the Fedora community in one place. This is an iterative work-in-progress.

CC: @bt0dotninja @rowright @not-a-dev-stein @josephgayoso I thought this might be a fun project, to start writing out a dictionary of sorts for Fedora vocabulary. Happy to incorporate more edits or other important acronyms here. 🙂