SQLite Migrations: Rebuild tables

[bricelam]

More tests to come, but I think we can get something merged and iterate on it.

Fixes #329

[bricelam]

Design meeting notes:

• We don't need to warn that we're doing a table rebuild because they're so pervasive on SQLite that it would just become noise
  • But we should definitely consider warning if we do this on other providers
• Verify what happens with self-referencing foreign key constraints
• We only need to create indexes before the INSERT if they're new
  • Existing UNIQUE indexes already ensure that the data is valid
  • We can create them under their actual name since they won't conflict