Added setAlwaysOn feature

Add setAlwaysOn() system api.
This API is used to request that the NFC service
shall kept controller state on.

Add isAlwaysOnEnabled() system api.
This API is used to check setAlwaysOn is enabled or not.

Add isAlwaysOnSupported() system api.
This API is used to check setAlwaysOn is supported or not.

Bug: 176212892
Test: manual
Change-Id: If7ece9730c57838d870bb70cb2725919e75ef6c2