Add JSON <=> DB utils, unpack compendia to JSON so we can track them

[rsek]

note that about 1,000 of the 1,006 changed files are just JSON exports from the DBs. the actual data is unchanged in this PR, so they don't require review.

• adds a couple build-time dependencies, fs-extra and the FVTT CLI
• adds some typings for FVTT CLI (they aren't provided so i had to DIY them)
• cleans up a couple unused, empty DBs that the CLI was complaining about not being to iterate over
• adds two scripts to scripts, to pack/unpack the DB files to/from JSON, plus a couple constants so the new scripts know where to look
  • i think they could be run as part of CI, but i haven't actually tested this yet

[ben]

LGTM