Add GET and OPTIONS route for /milestones/:id

Change-Id: I903b89e02915d116d1fed86e5c648fe1bf907347
Add GET and OPTIONS route for planning/:id/milestones

Change-Id: If3e143ac85e62d98d6770d5e2b9001c3b798f448
Add GET and OPTIONS route for plannings/:id/backlog

Change-Id: I4248a0c82eb73ead04bf3ac0ca9bb66c011e330b
Add GET route for /trackers/:id

Change-Id: I69f6f5fa3547b981f6a32588e436f0a9c34fa902
Fix GET /trackers/:id route

Change-Id: Ied7c8aaa37f142e2b22ef2a8f888accb34a1bfb0
Add OPTIONS /artifacts/:id

Change-Id: I1a4b69f1fb4a8f24507b894cf91c08c40281a4ce
GET /artifacts/:id infos

Change-Id: I55e4b46c83381c018b6d303c79d43cedb877645c
Add GET artifacts/:id/changesets

So we can list all artifact history

Change-Id: I532ae3e76b3330bab9692711bfe117d5f7f16489
Duration can be misleading (week-end)

Change-Id: If3e714e558d57b5e6f450b13253f7a0e1c725848
Separate submilestones in a dedicated route

Change-Id: I063e6d2521879319a7e2c0d4fad67736a405c929
Harmonize planning implementation

* Route is now "plannings" (/projects/:id/plannings, /plannings/:id/milestones)
* Plannings reference trackers using {id, uri} object

Change-Id: I6948907b9fff2f9173ad6700d13538b8fc7990f8
tasks #5512: link planning resources to project

Change-Id: Iad6ac0a0f45fd7f6df7517b0927fcb27dd05bba8
Add link to planning milestones

Change-Id: Ibb311d9bf5041cffc6a16d9920edb6bca9b5a760
Adapt backlog_items to what we can actually manage

Change-Id: Id90855854c49fe86a602b361afa6adc0e1d17348
Distinguish status and status_value

* status_value corresponds to the actual value of a field pointed by the status semantic (Planned, todo, on going, etc)
* status corresponds to the status semantic value (Open/Closed)

Change-Id: I7c325443a0c946003e9d60acb5f07039d6b6d9c0
Match REST implementation and REST wiki specifiction

Change-Id: I3b10f3874ccebb840c8e54f0654be43d85369b69
Fix resources usage

* As per convention, routes are defined in "Representation" objects
* The planning is under responsability of agiledashboard plugin, so it must not
  leak into the core

Change-Id: I52e29d0abf63d554357986ed8eeb49bfa71f47de
Fix tasks #5536: forbidden when project is private

Change-Id: Ie6fc396a6c0df3162942fc60a0949eeea225f4f8
Merge remote-tracking branch 'stable/master' into 5442_rest_milestone

Conflicts:
	plugins/tracker/include/autoload.php

Change-Id: I4d635d76c3e518b0c2bbecde39c2cab1d2a8c3bd
Merge remote-tracking branch 'gerrit/5442_rest_milestone' into tuleap-stable-master

* gerrit/5442_rest_milestone:
  Fix tasks #5536: forbidden when project is private
  Fix resources usage
  Match REST implementation and REST wiki specifiction
  Distinguish status and status_value
  Adapt backlog_items to what we can actually manage
  Add link to planning milestones
  tasks #5512: link planning resources to project
  Harmonize planning implementation
  Separate submilestones in a dedicated route
  Duration can be misleading (week-end)
  Add GET artifacts/:id/changesets
  GET /artifacts/:id infos
  Add OPTIONS /artifacts/:id
  Fix GET /trackers/:id route
  Add GET route for /trackers/:id
  Add GET and OPTIONS route for plannings/:id/backlog
  Add GET and OPTIONS route for planning/:id/milestones
  Add GET and OPTIONS route for /milestones/:id

Change-Id: I35c1d381eaa42ce0c6c9e0a659b25bda172d9b73