add a connection pooler for the pgstac database

[hrodmn]

Everytime I talk to @bitner about deploying pgstac with serverless deployments of applications like titiler-pgstac and tipg that read directly from the database he says adding a connection pooler is a good idea.

I tried adding an RDS proxy in front of a database once but it doubled the cost of the database deployment so maybe that's not the best option. Would it be a good idea to add a tiny ec2 instance running pgbouncer in front of the pgstac database?