Show "Link" item when applicable and show correct toast for deletion.

b/25165853 is about the "Link" item. And this CL also does the following
things:

1. show toast for deleting 1/multiple contacts from PeopleActivity.
2. show toast when deletion happens in QuickContact and contact editor.

Bug: 25165853
Change-Id: Ia8ecb6b4118ecff3bc3ba50ac98ffadf337db52c