Write models for custom config validation

[uniqueg]

Is your feature request related to a problem? Please describe.

Since v0.9.0, FOCA supports the validation of custom config params when provided with a Pydantic model class: https://github.com/elixir-cloud-aai/foca#custom-configuration

Describe the solution you'd like

Implement the models in file pro_wes/config_models.py and pass to Foca() constructor in pro_wes/app.py.

Additional context

This functionality is currently already implemented in proWES, so that could be used as an example/template:

• Models
• Foca() instantiation