refactor(client): Move many parameters/helpers from Session to Relier.

parameters:

* service
* most oauth parameters
* redirectTo
* context

helper functions:

* isSync
* isFxDesktop

Other work:

* Split of the OAuthRelier from the normal Relier
* Initialize Channels with the Relier in app-start
* Update the oauth-reset-password functional test to not hard code the email format. Instead fetch the link from the email headers.

Remove all of the resume stuff.

issue #1648