Support the performant taxonomy model in the new taxonomy field / Experience Manager

In CMS-14091 a new taxonomy model was introduced on 15.3, moving the locale related properties 'name', 'description' and 'synonyms' (a multiple) two levels up, from hippotaxonomy:categoryinfo sub-subnodes to the hippotaxonomy:category node.

This needs to be ported to 15.3-taxonomy branch,

• checked for TaxonomyFieldPlugin, should be good since it's talking to JcrCategory/JcrCategoryInfo
• reimplemented on the TaxonomyPicker in the Experience Manager (TaxonomyFieldTypeUtils).