core_services: Bundle clipboard, window_manager, and view_manager.
This moves clipboard, window_manager and view_manager into the same
core_services.mojo physical library, letting us share the core mojo and
base code in said library. We make core_services a packaging detail of
mandoline, and only set up the aliases in the mandoline binary.
This is the first pass at starting each of these applications on their
own thread.
BUG=477435
Review URL: https://codereview.chromium.org/
1131703002
Cr-Commit-Position: refs/heads/master@{#328866}