tasks #6697 and tasks #6698: Tracker color can be selected in general settings

Change-Id: I360f879cf29b70e57c1bf1b5d9f45eda2cf2888d
task #6699: Export and import tracker color in XML

Change-Id: I402dda2c1cf1b3bead2162797270b8d05e1cc590
task #6700 - Keep tracker color in duplication

Change-Id: I9dc1b20cdf33e49eeeecb69467ebefc45cad3eac
Merge commit 'refs/changes/97/2297/4' of ssh://gerrit.tuleap.net:29418/tuleap into stable

* ssh://gerrit.tuleap.net:29418/tuleap:
  task #6700 - Keep tracker color in duplication
  task #6699: Export and import tracker color in XML
  tasks #6697 and tasks #6698: Tracker color can be selected in general settings
This is Tuleap 6.12.99.51

Change-Id: I7f4c3a8d76c7b03375d2d9e3fca5235674ac474f