Add GET and OPTIONS route for project/:id/trackers

Change-Id: Ifda035a245d9a6cc13e97c468bce7b1b561a610e
Merge remote-tracking branch 'gerrit/5582_project_trackers' into HEAD

* gerrit/5582_project_trackers:
  Add GET and OPTIONS route for project/:id/trackers

Conflicts:
	plugins/agiledashboard/include/autoload.php
	src/common/event/Event.class.php
	src/common/project/REST/v1/ProjectResource.class.php
	tests/rest/ProjectTest.php

Change-Id: I62421c837f02773bc26498daeaa7167e82fe3c44
This is Tuleap 6.7.99.12

Change-Id: I2c7a5cabb056d07603970e55046e141da7bfa3bd