Use puppet logic to not copy language list

Originally created by @hefee on #16450 (Redmine)

We have a copy of languages in files/weblate/scripts/update_tm.sh:

UPDATE_LANGS="ar ca de es fa fr it pl pt sr_Latn tr ru zh zh_TW"

this script should be replaced with a template, that using the list of all languages from manifests/weblate/languages.pp, like done for langs.json.

Parent Task: #16436 (closed)