CC-4904: Library -> Sort by status doesn't work

- added 2 columns to cc_files (is_scheduled, is_playlist)
- split library status column into two columns (scheduled, playlist)
- is_scheduled gets updated when a track plays out, or when a file gets added/removed from/to a show
- is_playlist gets updated when a file gets added/removed from/to a playlist/block, when a playlist/block gets deleted, or when a playlist/block's contents is cleared

airtime_mvc/build/sql/schema.sql

@@ -98,6 +98,8 @@ CREATE TABLE "cc_files"
 	"cueout" interval default '00:00:00',
 	"silan_check" BOOLEAN default 'f',
 	"hidden" BOOLEAN default 'f',
+	"is_scheduled" BOOLEAN default 'f',
+	"is_playlist" BOOLEAN default 'f',
 	PRIMARY KEY ("id")
 );