♻️ Add minor refactor to file migrations

Relevant changes:

- Add the ability to create migration in both directions, defaulting
  to identity if not provided
- Move the version attribute to file table column for to make it more
  accessible (previously it was on data blob)
- Reduce db update operations on file-update rpc method

backend/src/app/migrations/sql/0119-mod-file-table.sql

@@ -0,0 +1,2 @@
+ALTER TABLE file
+  ADD COLUMN version integer NULL;