CI observer: Allow regexp filtering for Postgres logs before sending to the Platform

Goal

As a DLE admin, I can set up regexp rules for Postgres logs. These rules are applied before sending the logs to the Platform, to ensure that personal data is masked properly.

TODO / How to implement

• Extend database Lab configuration

  observer:
    replacementRules: 
      "regex": "replace"

• Build a map of processing fields

  Processed Fields:
     - message
     - detail
     - hint
     - internal_query
     - query

• Replace matched strings

  Regex syntax: https://github.com/google/re2/wiki/Syntax

• Add regex tests

• Add docs

Acceptance criteria

As a DLE admin, I can set up rules to avoid sending personal log-data (Postgres logs) to the Platform.