Add PUT Route to Config API

[KevinMackenzie]

One major feature of the API is to allow the server to update their configuration state. This will allow them to do that by submitting JSON to a route TBD with the applicable information. The format of this is also TBD, but will contain the name of the config, the db_lines and the local_lines.

[KevinMackenzie]

More or less complete with b07047b (pending more rigorous testing).
While the API will request JSON with anything in the fileName attribute while PUTting since the API uses the name in the URL, we should validate that either: the fileName in the JSON is blank OR is equal to the one in the URL.