R1:86040227b0b5

Improve Aphlict server

Summary:
- Move to port 22280 by default.
- Warn when running as non-root.
- Allow subscription and publish/admin ports to be configured.
- Allow server to drop root after binding to 843.
- Allow log path to be configured.
- Add /status/ admin URI which shows server status.
- Return HTTP 400 Bad Request for other requests, instead of hanging.
- Minor formatting cleanup.

Test Plan:
Ran without root:

$ node aphlict_server.js

...got a good error message. Ran with…