All items have unique ids

[pacampbell]

Modified item storage to be such that all items has a UID, even if they are the exact same item.

Created a script uid_migration_script.py which can be used to migrate an existing sqlite3 database to the new required layout.

Requires #350 to work correctly.

Checklist:

• [x] The project compiles
• [x] The PR targets develop branch

[Conner-Schaffer]

I noticed you didn't change schema_postgres.sql and schema_mariadb.sql was that intentional? I think they need to be updated too.

[alborrajo]

I noticed you didn't change schema_postgres.sql and schema_mariadb.sql was that intentional? I think they need to be updated too.

Only schema_sqlite.sql have to be updated. The rest get auto-generated from the sqlite script when using either of thos two options

[pacampbell]

Removed #350 in anticipation of the merge.