UX: improvements to new dashboard

- remove inactive user report and replace with posts
- clean up internals so grouping by week happens on client
- when switching periods old report was not destroyed leading to bugs
- calculate trend based on previous interval ... not previous 30 days
- show percentages for mau/dau
- be more careful about utc date usage
- show uniqu and click through rate on search panel
- publish key of report with report so we only load the correct one
- subscribe earlier in channel in case of concurrency issues

test/javascripts/models/report-test.js.es6

@@ -60,4 +60,4 @@ QUnit.test("thirtyDayCountTitle", assert => {
 
   assert.ok(title.indexOf('+50%') !== -1);
   assert.ok(title.match(/Was 10/));
-});
+});