Validate Wingman on start and let them fail gracefully

[Shackless]

Currently, the entire programm crashes/closes if there's a Wingman with a faulty config or missing required config entries.

• Add a function to Wingman base that derived classes can override to validate required params (like xyz_api_key).
• Tower should try/catch this function and disable a Wingman if the validation fails
• Wingman status should be shown in the UI.