Decouple extraneous dependencies and code from RestController

RestController is due for revisiting to clean up the code since it's been a few years.
- OpenApiDocumenter would benefit from its own Controller class to clean up the code.
- Special route handling can be added for Favicon.ico (or even just add favicon to the project)
- Cleanup `DeterminePutPatchSemantics` function which is currently multi purpose: reject etag usage and swap out operation types.
- This should be split into two: middleware for rejecting etag usage (until we eventually support it), and just using expected operation types in restcontroller put patch routes.