Allows to launch only authenticator owned activities

Allows to launch only authenticator owned activities

- 3rd party developers can define himself-authenticator
  and use the accountPreferences attribute to load the
  predefined preference UI.
- If a developer defines an action intent to launch the
  other activity in xml and it would return true due
  to the true exported attribute and no permission.
- To avoid launching arbitrary activity. Here allows
  to launch only authenticator owned activities.

Bug: 150946634
Test: make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.accounts
Test: PoC app
Change-Id: I5ce1a0b3838db7b3fbe48c6ea23d5f093d625cdb