Chooser custom actions API.

A proposal for the new API for custom Chooser actions.
A new extra flags for Intent, EXTRA_CHOOSER_CUSTOM_ACTIONS and
EXTRA_CHOOSER_PAYLOAD_RESELECTION_ACTION.
EXTRA_CHOOSER_CUSTOM_ACTIONS can be used with intent action
ACTION_CHOOSER to provide a collection of application custom that would
be present to the user in the sharesheet. ChooserAction class is a new
data for carrying app-specified actions.
EXTRA_CHOOSER_PAYLOAD_RESELECTION_ACTION extra flag for content
reselection custom action.

Bug: 258838272
Test: smoke build test, the API is not used at the moment.

Change-Id: Id6748c01ad84cc8ec4a1bc7010e2b82812def9ad