Initial implementation of EAS security

* This first implementation integrates with early CLs for
  Email app integration with device security
* Check for policies added to validation process
* If the server has no policy requirements, there is no change
  to the existing process
* We automatically declare a set of policies to be unsupported
  if any are known to the sync adapter to be unsupported
  (e.g. no attachments or password history)
* We call isSupported (PolicySet) to determine whether other
  policies use values that the OS can support (e.g. password length,
  inactivity time, etc.)
* Depending on whether the server's policies are unsupported or
  supported, we throw the proper exception back to the caller

Change-Id: I704cb2151dd87f54c83c2aa23976a8ac8e2c501a
3 files changed