Test pgSTAC deployments on Aurora.

[sharkinsspatial]

To better support some future work on high availability / multi-region pgSTAC deployments we should support deploying pgstac to Aurora for easy multi-region replication cc @j08lue @anayeaye.

[vincentsarago]

FYI tipg won't run in Aurora as is developmentseed/tipg#85 (comment)
but it's possible to create a custom TiPg application developmentseed/tipg#85 (comment)

cc @bitner