UI/Inputs: tagify and errormessage for datetime (merges from trunk) (ILIAS-eLearning#3615)

* UI/Input: 31269, add problembuilder to required-validation

* UI, TagInput: add dependency 'tagify', remove 'typeahead' and 'bootstrap-tagsinput' (ILIAS-eLearning#3466)
* UI, TagInput: add dependency 'tagify', remove tpyeahead and bootstrap-tagsinput
* UI, TagInput: use tagify for tag-input, adjust component, template, test
* UI, TagInput: add label-for, remove debug code, color-vars in variables.less

Author: nhaagen

lang/ilias_de.lang

@@ -16620,3 +16620,5 @@ prg#:#will_not_modify_validity_on_non_successful_progress#:#Gültigkeit kann nur
 prg#:#status_unchanged#:#Status unverändert
 content#:#cont_media#:#Bilder/Audio/Video
 content#:#cont_sur_block_format#:#Umgebender Block
+ui#:#datetime_required#:Zeit/Datum erforderlich
+ui#:#duration_end_must_not_be_earlier_than_start#:#Der Beginn muss zeitlich vor dem Ende liegen.

lang/ilias_en.lang

@@ -16607,4 +16607,6 @@ prg#:#will_not_modify_relevant_progress#:#already relevant
 prg#:#will_not_modify_validity_on_non_successful_progress#:#Can change only when successful
 prg#:#status_unchanged#:#Status unchanged
 content#:#cont_media#:#Images/Media
-content#:#cont_sur_block_format#:#Surrounding Section
+content#:#cont_sur_block_format#:#Surrounding Section
+ui#:#datetime_required#:Time/Date required
+ui#:#duration_end_must_not_be_earlier_than_start#:#Start must not be later than end.