Cleanup: Rename constants to improve readability
Cleanup: Just save the build versions

There is no need to check for keys existence because we are initializing a
blank database.
Cleanup: Move code to separate function on initdb
Cleanup: Simplify code by merging functions
Cleanup: Remove intermediate function to save legacy build version
Cleanup: Remove unnecessary Meta from form

It appears to be used on djblets templates that are not used.