Export License DB

Problem to solve

GitLab instances need to stay in sync with the External License Database. That includes the offline instances that can't directly query the External License Database (in case it has an API).

Proposal

Export the External License Database automatically, so that GitLab instances can sync with it.

For instance, the export could be:

• an SQLite DB the consumer instance would query to selectively fetch what it needs (license data of components used as project dependencies in the instance)
• a sequence of files (CSV files or raw SQL files) that consumer instance would track and import to do a full sync; this would be similar to an incremental backup

See #372212 (comment 1091629850)

We assume that the license data coming from the External License Database is immutable.

The syncing of the GitLab instances is covered by a separate issue. TODO: create issue

TBD: Access restriction, if any. See #372212 (comment 1084619701)

cc @gitlab-org/vulnerability-research @sam.white