Fix stats calculation

Do not run all cached methods (CachedMethods.all) when calculating
a specific one.
Fix dirty flag decrementing

Decrement dirty treeitem scores (flags) after all treeitems (from a Store to a
project) have been updated. If cache updating failed we could have inconsistent dirty treeitem
scores.
Fix time format in reports
Update moment.js version to 2.8.3
Add retry failed jobs command
Use separate widget for user rates instead of readonly form
Change view permissions for user report

Show user report and detailed without payment info to everybody
Show summary, paid tasks, user rates, add paid task form to user himself only
Show contact form on `remove paid task` click