"bug"/confusing feature: the RawRouter doesn't default to Raw codec

[jsoverson]

Describe the bug
The RawRouter defaults to the Json codec which means you get JSON-stringified base64 bytes if you try to return what most would consider a "raw" HTTP body to be.

To Reproduce
Create a raw HTTP router component and return JSON bytes as the response (w/ JSON content-type header)

Expected behavior
The HTTP response looks and feels like normal JSON

Actual behavior
You get a base64-ed string that – when decoded – is the JSON you'd expect.

Proposal
Change the default codec for the Raw router to be Raw instead of Json.