ShortcutManager: API changes for DR

See https://goto.google.com/shortcutmanager-spec-dr for
the details.

This CL contains changes to ShortcutInfo and all the new API
entry points, but not the implementation of the new APIs.

- ShortcutInfo.activityComponent is now mandatory.
- Publishers can now disable shortcuts.  ShortcutInfo can now have
"disabled message".
- ShortcutInfo now supports string resources for all the String
fields.
  -> When launcher fetches shortcuts, ShortcutService will
  automatically load resources and expose as strings.
- LauncherApps now supports getShortcutIconDrawable() and
getShortcutBadgedIconDrawable() to be consistent with
LauncherActivityInfo.

- ShortcutInfo.weight is replaced with "rank".

- Added ShortcutManager.reportShortcutUsed(), which will be used for
usage tracking / suggestion.

Bug 28536054
Bug 28536066
Bug 28564134
Bug 28594168

Change-Id: Ib8245b39bb1e753991a9de89c0b73accacd90355