Remove proto/api submodule

[dnr]

What changed?

• Remove proto/api submodule.
• Adds a new program that's automatically run by the Makefile as required to output the api protos in binary form, which can be used by most tools. The command is run by go run and uses the same api-go reference as the rest of the server for the source protos.
• Removed http annotations from internal matchingservice proto.

Why?

• Ensure that the api-go import (in go.mod) and the proto files imported by this repo's proto files are always in sync.
• Simplify update process, stop having to mess with submodules.

How did you test it?

running commands manually a lot

Potential risks

Importing protos from somewhere other than our api and google well-known protos may require some updates to the script's import path logic.

Documentation

updated docs

[dnr]

Your protogen version is out of date as we pin protogen in the makefile; it's separate from the Go API version in go.mod

I know, I'm waiting to do an api release so I can bump it