Fix postgres connection options causing slow query speed.

[dessalines]

This fixes a query speed issue introduced by 78702b59fd56f767f3d5612bfd60e294979f91f8

This fixes one slow query problem by

• Properly passing lemmy options in the connection URI string, rather than running a SQL command before every query.
• Comments out some settings that caused the slowness.

Context: #5149

[dessalines]

@dullbananas when you get a chance, could you help me look at this CI error? We only get it when running on the CI, running either db_perf or cargo test locally doesn't have this issue.

It has to do with moving the options to the connection URI, rather than running them before every query.

Database migrations complete.
Error: Error occurred while creating a new object: database "lemmy&options=-c geqo_threshold=12 -c lemmy.protocol_and_hostna" does not exist

https://woodpecker.join-lemmy.org/repos/129/pipeline/9827/16#L243

[dullbananas]

You probably need to make it correctly choose between ? and & based on whether or not the URI already has ?

[dessalines]

@dullbananas That did it, thx!