First shot at (host-based) card emulation APIs.

HostApduService: convenience service class for implementing
a service that registers a set of ISO7816-4 AIDs and emulates
the corresponding application inside the service itself.

SeApduService: convenience service class for implementing
a service that registers a set of ISO7816-4 AIDs that reflect
applications installed on an embedded secure element or UICC. Contains
event hooks to allow the service to handle eSE/UICC events that
correspond to those AIDs.

Change-Id: I44191bd4abcbbe4f1fd36a9fd42639fe5c0cf496