renamed MediaWords::DBI::Controversies to MediaWords::CM (better matches the naming used in other parts)
"create controversy" button, form, controller action and helper subroutine in the model
show the status of the initial SearchStories Gearman job if no such job has been finished
make dashboards "public" or "private"; show only public dashboards in the "create controversy" page
change the <select> of media sets IDs to checkbox group to:
* include a short description of each dashboard in the same page (not a popup)
* enable multiple selections without pressing Ctrl + Command
check the "create controversy" form values correctly
Merge branch 'master' into cm_create_controversy
Merge branch 'master' into cm_create_controversy
Merge branch 'master' into cm_create_controversy
Merge branch 'master' into cm_create_controversy
Merge branch 'master' into cm_create_controversy

Conflicts:
	sql_migrations/mediawords-4430-4431.sql
Merge branch 'master' into cm_create_controversy
Merge branch 'master' into cm_create_controversy

Conflicts:
	lib/MediaWords/Controller/Admin/CM.pm
Merge branch 'master' into cm_create_controversy
Merge branch 'master' into cm_create_controversy

Conflicts:
	sql_migrations/mediawords-4430-4431.sql
Merge branch 'master' into cm_create_controversy
Merge branch 'master' into cm_create_controversy

Conflicts:
	lib/MediaWords/DBI/Controversies.pm
misc fixes after merge
merge database update
optimize health pages; add tag_sets page