Docker migration removed pgbouncer

[bwbroersma]

It looks like pgbouncer was used before the docker migration:

• Do not run migrations against pgbouncer and consider optimising #768

I'm unsure what is using connections, if more than 100 connections are used (e.g. by using a lot of workers?) connection pooling should be used, maybe include it in the docker setup?

[aequitas]

Looking at the metrics we never hit 100 connections, on average a maximum of 10 connections are used.