Disable PAN Reverse Tethering when connection originated by the Remote

* Check for valid interactions between the three PAN profile roles per
  Table 1 in PAN Profile v1.0 spec.
* Explicitly disable connections to the local PANU if the remote is
  not PANU.

Bug: 63145701
Test: External script
Change-Id: I29a7e404ba7e4453b6a7c59148a2b3eb7395303a
Merged-In: I29a7e404ba7e4453b6a7c59148a2b3eb7395303a