Code Jam Extension Facelift

[D0rs4n]

Before the Code Jam some features (the majority of them) weren't implemented in an optimal manner, hence a facelift PR is required.
A few notes from previous PRs:

• There is a common pattern in Sir Robin where we get a team, handle possible API errors, and the proceed with the data gathered from the API. This procedure should be moved to a helper function.
  • Return the data as dataclasses (/pydantic models), so that we don't have to slice dicts everywhere.
• Set the Textbox's type to be TextArea when adding notes.
• Utilize jam_categories upon cj create

If anyone has suggestions, please mention below this issue.