Federation and handler refacoring with huge cleanups and optimizations

[peppelinux]

This PR:

• adds a default_client_id and the possibility for each trust evaluation handler to use different client ids (experimental due to the LSP Potential requirements)
• aims to remove all the duplicated code and overlapping classes born during the refactoring from 0.7 to 0.9, with the scope to simplify the implementations
• extends the configurations and consolidates the example configuration to provide a more appropriate guidance to the implementers
• removes the deprecation warning about pyhdantinc FieldValidationInfo
• ...

[peppelinux]

these three should be cleaned up too