Drop router table, move router data to message table

[bbangert]

Per design discussion at:
https://groups.google.com/a/mozilla.com/forum/#!topic/push-service/AJv5hy0UpkU

We will drop the router table, and store the previous router data for users in the message table under the blank record that records the valid channels.

This issue is block by dropping Simplepush:

• Issue End server support for SImplePush #799

This code will need to:

• Migrate existing router data to message table
• Begin checking message table for data before falling back to router table
• Move router table calls to manipulate the data in the message table instead

[bbangert]

Not feasible, as the router table acts as a separate connection throttle from our message table handling.