Remove database event tracking

Problem

We introduced tracking of database events via Snowplow through multiple iterations, most recently in #390827 (closed). This was done to test out whether Snowplow could be used to create a replica of our database.

Within https://gitlab.com/groups/gitlab-data/-/epics/880#note_1474689144 it's described that the PoC led to discarding Snowplow as a viable option for data replication. This is also confirmed in #390827 (comment 1562890019).

Now this is just dead code which can lead to confusion.

Desired Outcome

All code regarding the sending of database events to Snowplow is removed.

Potential Solution

TBD

Further Actions

TBD