* Refactor seafevents msg and add traffic stats API
Squashed commit of the following:
commit 85fe5369f711e1514762d93008f9ebb3c5d49041
Author: zhengxie <xiez1989@gmail.com>
Date: Mon Aug 6 15:48:55 2018 +0800
Add '-link' to access_token op type when generate download/upload link
commit 1817833fc3374f54030e16f3a1283ff6f34ddbf5
Author: zhengxie <xiez1989@gmail.com>
Date: Mon Aug 6 15:28:38 2018 +0800
Refactor file/dir events
1. Remove traffic related msg
2. Rename seahub.stats to seahub.audit for audit related msg
* Fix share link zip task traffic owner
* [admin api] Add org traffic
* [system admin] statistic: added 'traffic', fixed 'storage'
* [system admin] statistic: added 3 more charts for 'traffic', and modified the top nav
* [system admin] statistic: added 'traffic' for org; added a traffic nav, improved chart dot title
