tasks #7422: Define base mapping format

Refactor the way we put artifact informations into Elasticsearch:
- Follow-up are stored as part of artifacts
- A (base) mapping is defined per tracker
- Each add/update of follow-up is just an artifact update

Note: you must destroy and re-create your 'tracker' index first (see Readme)

Story #7342: FTS tracker: Tracker Creation Event: put mapping in ES

Change-Id: I52247edafa6540200c18ba413b94cb4d4567a8ba
Merge commit 'refs/changes/84/2984/5' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  tasks #7422: Define base mapping format

Change-Id: I06cd9826e92e3bf9ec3aae6b4b46875f911baf3c
This is Tuleap 7.4.99.27

Change-Id: I9a09dac5b91bfa2462e7c2508c9f48847661f6a6
tasks #7427 Index at artifact updates

"Follow-up add" event is removed in favor of generic one "Artifact Update"

story #7392 FTS tracker: Tracker Creation Event: put mapping in ES

Change-Id: Iaa143c5ad873ebe639ff987840c88d0fa44df5d1
Merge commit 'refs/changes/85/2985/5' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  tasks #7427 Index at artifact updates

Change-Id: Ic8a6d70ca24290c5525865197dc2cfddb2d5b437
This is Tuleap 7.4.99.28

Change-Id: Ie1a651884e51a51c5feb2616c70db473d293677d