Give warnings if dupe account created:

* Check for existing accounts with matching servername + username
* Show a dialog and block account creation
* Triggers in three cases:
  * After input of an auto-setup account (e.g. Gmail or AOL)
  * After input of manual setup (incoming) parameters
  * After changing incoming parameters of *any* existing account
* Made some notes in EmailContent regarding fields in HostAuth that we
    are not actually using.
* Added HostAuth unit tests

Primarily fixes bug # 1964449
Bonus fix for bug # 1594408

Change-Id: I49310faf6654280582e0ab3d3e40f2701bfcd21d
1 file changed