Merge pull request #872 from romainneutron/stable-dependencies

[3.8] Use a stable version of Get-In
Merge pull request #871 from romainneutron/fix-1646

[3.8] Fix #1646 : Unable to mount collections
Merge branch '3.8'

Conflicts:
	lib/Alchemy/Phrasea/Controller/Admin/Databox.php
	lib/classes/collection.php
	templates/web/admin/databox/databox.html.twig
Decouple caption and its serialization
Add elastic-search engine support