Document the endpoints using OpenAPI 3.0

[aabounegm]

Document the API endpoints using OpenAPI 3.0 so that it can generate Swagger (or similar) documentation.

views:

• product
• variety
• project
• activity
• account
• application
• notification

Models:

• product
• variety
• project
• activity
• account
• application
• notification
• Separate schemas for request and response (or use readOnly and writeOnly)

Security:

• Specify permissions (admin, user, project moderator, project creator)

other:

• more descriptive response descriptions and summaries
• use operationIds that coincide with the function name in the Flask code
• use descriptions from the endpoints' docstring
• use x-tagGroups for Redoc grouping
• document the different responses for the same response code (using oneOf. Ex: multiple possible error messages for the code 400)
• Add externalDocs that point to Notion pages