First step in simplifying MailAppProvider/app startup

Define a resource that specifies which content provider uris should be used
to get the account list.  This removes the need to have the extra code to handle
various provider/receiver startup orders, as only after MailAppProvider is
in onCreate() will we attempt to load the account list

Change-Id: Ief5f188bf1663fcc1c389c5ce48e2173b474f6ea
5 files changed