MBS-7664: beta: Cannot add release without release group

I'm guessing a68fc7fc16b182bf302e4aa27b22f9a7ba011178 caused the gid
property to no longer get added if it's undefined, which means we now
have to be explicit when referencing it from inside a data-bind,
otherwise a ReferenceError is thrown.
MBS-7666: Update DB_SCHEMA_SEQUENCE to 20
MBS-7667:  GenerateSQLScripts doesn't check for the existence of CreateTables.sql

find_search_path and process_tables assumed CreateTables.sql does exist,
which might not always be the case, so check for that.
Merge remote-tracking branch 'mineo/mbs-7666' into beta

* mineo/mbs-7666:
  MBS-7666: Update DB_SCHEMA_SEQUENCE to 20
Merge remote-tracking branch 'mineo/mbs-7667' into beta

* mineo/mbs-7667:
  MBS-7667:  GenerateSQLScripts doesn't check for the existence of CreateTables.sql
Merge remote-tracking branch 'bitmap/mbs-7664' into beta

* bitmap/mbs-7664:
  MBS-7664: beta: Cannot add release without release group
Update pot files using current code and production database.
Update translations from transifex.