feat: Support all pydantic model's field types

[dsowinski2]

This PR changes a way of handling agent, sources and integration arguments with json schema.

Now it can handle all types of Pydantic model parameters (Lists, Enums, Optionals etc.)

Enthusiast Common:

1. Added check for Union types - No more than 2 types and one of them must be None. This will guarantee that form receive strict field type.
2. Each Optional Field received default None

BE:

1. Agents, sources and Integrations types endpoints are simplified and now returns Pydantic's model_json_schema()

UI:

1. Added RJSF lib to handle forms based on json schema
2. RSJF templates customization
3. RjsfForm component for handling all configuration args

[mateus-po]

if properly tested with different argument types - LGTM