Postgres Pickup Repository using pg_bouncer

[jamshale]

At high scale and with multiple mediator pods the service would benefit by using pg_bouncer for the pickup repository and also the askar storage.

The pickup repository uses LISTEN/NOTIFY on the postgres connection. This won't work on the pg_bouncer connection, so it will need to connect to the actual postgres connection to enable session connections.

There may be issues with the askar connection using pg_bouncer. This will need to be investigated.

[jamshale]

I'm actually leaning towards this being a won't do. There's been a lot of improvements with postgres and the connections are in general very short.

Will leave open for now while we conduct our scaled load testing.