This change introduces a task viewer component to the UI
which will allow users to monitor the progress of long
running tasks without having to stay on a particular tab.
Tasks are created and attached to CTL event processors and
injected into phase clients so that status message updates
can be displayed dynamically.
Still TODO at some point is utilizing backend caching to tie
tasks to the users who initiated them so that browser refreshes
(i.e. new session IDs) won't empty the task viewer for that user.
Change-Id: I38aa03d2660d1fcc2bad6ecda718015602e25b6a
587031c09f