Teach config.go about the Riseup! Hidden Service

The current Riseup! hidden service is:

  ztmc4p37hvues222.onion

This .onion comes from the Riseup! chat documentation page:

  https://www.riseup.net/en/chat
Merge pull request #15 from ioerror/master

Add additional Hidden Service to config.go for Riseup! chat service
Consolidate the well known Hidden Services.

Having the repeated code looked a bit weird, so pulling it all into a map and
doing it that way seemed a bit cleaner to me. Also, as a bonus it's easier to
add more "well known" hidden services later.

This assumes that they are always going to be running on port 5222, is this a
reasonable assumption?
Merge pull request #16 from rmoore/well_known_tor_hs

Consolidate the well known Hidden Services.