Use I/O validation for flask-restx

[nikromen]

We don't use flask-restx parsers since the documentation says the parsers will be no longer developed and they recommends using packages that handles I/O better - marshmallow or pydantic.

This is basically follow-up for #2807 to prevent it to become huge - the schemas for validation are there in shema/schemas.py and are written using dataclasses which uses basically the same structure that pydantic/marshmallow uses so the transition to it code-wise will be easy - the tricky part may be that we don't do validation right now with the dataclasses so there is a chance that some data will need some tinkering

parser docs - https://flask-restx.readthedocs.io/en/latest/parsing.html