Add new capability polling opt-in intent

Adds a new capability discovery opt-in intent,
which an application can use to prompt the user
to enable contact discovery.

Bug: 111305845
Test: atest CtsTelephonyTestCases; telecom test app
Merged-In: I42b9d7226a1296bc7e4e86a5ff6448bc8f23d3c0
Change-Id: I42b9d7226a1296bc7e4e86a5ff6448bc8f23d3c0