Adding Activity Action entry

In L we're bringing the notion of a device name, which centralizes a
concept that has been used in different part of the system already
(bluetooth and WifiP2p among others)

The settings entry has already been created, but there is no centralized
UI for setting the name yet.

This CL would define the activity action that would have to be
implemented to set the device name.

b/14970370 - Global Device Name

Change-Id: I6876e4ca1ad887fdea1bc88890ddfad547145011