R1:6d2d1d3a9770

Add `bin/garbage compact-edges` to compact edges into the new format

Summary:
Depends on D18947. Ref T13051. This goes through transaction tables and compacts the edge storage into the slim format.

I put this on `bin/garbage` instead of `bin/storage` because `bin/storage` has a lot of weird stuff about how it manages databases so that it can run before configuration (e.g., all the `--user`, `--password` type flags for configuring DB connections).

Test Plan:
Loaded an object with a bunch of transactions.