[FEATURE] added backend module ManageSynonyms

This module is built to maintain the synonyms for
every available core. It lists all synonyms and
allows to add synonyms. Delete is missing.

Related: #58173
Change-Id: Id3bc50a0b260b898ab80114e0184bbf12193c8d7
(cherry picked from commit 380b1366bd15b7f36479bb4c39fc39d708b45ce3)
Reviewed-on: https://review.typo3.org/30195
Reviewed-by: Ingo Renner
Tested-by: Ingo Renner