support "Record and Replay" on PGSQL

[staabm]

Todos

• extract a common SchemaHasher baseclass/interface out of SchemaHasherMysql
• Implement a SchemaHasherPgsql
• adjust ReplayAndRecordingQueryReflector to make use of the extracted SchemaHasher baseclass/interface
• update docs and remove the "Record and Replay is not yet supported on the PGSQL driver" notices

[FluffyDiscord]

@staabm any updates on the ReplayAndRecordingQueryReflector, and the rest of this?

[staabm]

Noone worked on it yet. Feel free to grab the task