chore: Slovak translation, enabling language and adding first translations (#14783)

* Slovak translation - enabling language and adding first translations

* Linting fixes

* Adding basic translations

* Slovak translation - adding json file

* JSON lint fix

* Prettier fix

Co-authored-by: Ville Brofeldt <ville.v.brofeldt@gmail.com>

superset/config.py

@@ -314,6 +314,7 @@ LANGUAGES = {
     "pt_BR": {"flag": "br", "name": "Brazilian Portuguese"},
     "ru": {"flag": "ru", "name": "Russian"},
     "ko": {"flag": "kr", "name": "Korean"},
+    "sk": {"flag": "sk", "name": "Slovak"},
     "sl": {"flag": "si", "name": "Slovenian"},
 }
 # Turning off i18n by default as translation in most languages are