App changes for account types with data sets.

This is primarily a replacement of the Android Account object in most
parts of the app with a new AccountWithDataSet object that extends
Account (by adding an additional attribute, the data set).

This also includes a major refactoring of the AccountTypeManager,
both to allow it to handle data sets and to allow for
non-sync-adapter packages to be referenced by the sync adapters for
an account and registered as sources of contact data. Attributes of
the sync adapter that would typically come from the authenticator
can be parsed out of the Contacts XML for these packages.

Bug 5077096

Change-Id: I88f311c64eae78c88e9999bff6f7de8538e62157