gitea.lister: Fix uid to be unique across instance
The gitea lister can be run on multiple instances which could use the same id. So listing another gitea instance, the current code would fail to insert data for such case.
This commit fixes that behavior by prefixing the uid with the instance name.
Related to #2577 (closed)
Test Plan
tox
Migrated from D3903 (view on Phabricator)