Add API proxy for Conductor

I think it's ready for a first review.

The steps to test is:
- Enable the module
- Add to the config page the api key and secret
- Make requests to the conductor api resources like using the route /conductor/api/{conductor-resource}
- /conductor/api/accounts

It should accept GET, PUT, POST and DELETE requests.

tim.plunkett → made their first commit to this issue’s fork.

Merged, thanks!