NetworkProtocol input/output validation and documentation

[rhythnic]

Create JSON schemas for the entities passed back and forth between NetworkProtocol handlers and the NetworkProtocol model. Validate results from handlers in the app. Validate both inputs and outputs in the tests.

Create in-code jsdocs for the NetworkProtocol handler methods.

[rhythnic]

Unnecessary. The networkSettings are validated before insertion into DB, which is sufficient for now.