Set max request size to 4MiB

[nsmith5]

Summary

Fixes the the max request body size to 4MiB (Just a guess at a size.... may it could be smaller?) so that it isn't unbound. Implemented using a new api.WithMaxBytes middleware. There is a small refactor of how we wire up stuff for the API server here as well to make it a little easier to understand. As adding the body limiting middleware was part of that wire up it seemed a good thing to clean up with this work.

Ticket Link

Fixes #335

Release Note

* Set max request size to 4MiB so that request size isn't unbound

[nsmith5]

The diff algorithm made this one a little odd to read. Sorry ya'll 😅

[dlorenc]

Thanks!