BugFix: Collection ID can't be null in the database

[slesaad]

Description

Right now, the collection id field in the database isn't set to not allow null.

We realised this when we accidentally ingested items into the database when the collection didn't exist, and it broke the whole stac api.

We should set the field as not null to avoid this in the future.

Acceptance Criteria

• Set id to not null