Timeouts and webfinger performance

Refs #217:

* Timeout interval for all requests is increased when timeouts happened, to account for slow connections (up to a maximum timeout of 45 seconds)
* webfinger discovery will attempt to fetch HTTP profiles only when the HTTPS requests failed. This means it will only spawn 3 requests at a time. I hope this improves performance on mobile, if it still is a problem we can reduce the request number even further.