Add static input validation for Page Editor

[twschiller]

Questions

• Use Yup or just write our own validation method? Using Yup might not be worth it because we need custom logic based on brick types and are also overlaying runtime errors (via traces)

Part of the Yup schema will need to be dynamically created based on:

• Extension type (affects which prop name is used for the block configuration pipeline)
• Number of bricks in the pipeline

Validation:

• outputKey format validation (must be valid identifier, i.e., start with a letter and only including letters and numbers). NOTE: effect and renderer bricks should not have outputKeys (the field is disabled in the UI)
• Panel/Sidepanel extensions should have exactly 1 renderer. (If there's more than 1, add a warning to each renderer after the first)