request #7636: Include Docman and Tracker plugins in frequencies graph

admin » plugins » statistics » frequencies (graph)

- rename "Document viewed" to "Legacy document viewed"
- add V3 mention for legacy tracker entries
- add hooks to let plugins insert their own data
- Docman plugin add its own sample based on plugin_docman_log.time
- Tracker plugin add its own sample based on
  tracker_artifact.submitted_on

This is based on a contribution by Sodern

Change-Id: I1c48a1779aef263608fa9c8e55f48967db56378b
Merge commit 'refs/changes/56/3256/2' of ssh://gerrit.tuleap.net:29418/tuleap into tuleap-stable-master

* ssh://gerrit.tuleap.net:29418/tuleap:
  request #7636: Include Docman and Tracker plugins in frequencies graph

Change-Id: I092f77f68e2528ff3c25c9fe288c494ba36734b2
This is Tuleap 7.7.99.37

Change-Id: Ia81ff135fa2cf5df527ca3b356bec7a7dd8e2a16