FEATURE: Localization admin settings config page (#31085)

This commit adds a new Localization config page for
admins, as a basic filtered site setting page similar
to Legal and Notifications. Included settings are:

* default locale
* allow user locale
* set locale from accept langauge header
* onebox locale
* display local time in user card
* discourse local dates enabled
* support mixed text direction
* unicode usernames
* allowed unicode username characters

plugins/discourse-local-dates/config/locales/server.en.yml

@@ -1,6 +1,6 @@
 en:
   site_settings:
-    discourse_local_dates_enabled: "Enable the discourse-local-dates feature. This will add support to local timezone aware dates in posts using the [date] element."
+    discourse_local_dates_enabled: "Enable the discourse-local-dates feature. This will add support to local timezone aware dates in posts using the [date] element"
     discourse_local_dates_default_formats: "Frequently used date time formats, see: <a target='_blank' rel='noopener' href='https://momentjs.com/docs/#/parsing/string-format/'>momentjs string format</a>"
     discourse_local_dates_default_timezones: "Default list of timezones, must be a valid <a target='_blank' rel='noopener' href='https://en.wikipedia.org/wiki/List_of_tz_database_time_zones'>TZ</a>"
-    discourse_local_dates_email_format: "Format used to display a date in emails."
+    discourse_local_dates_email_format: "Format used to display a date in emails"

plugins/discourse-local-dates/config/settings.yml

@@ -5,6 +5,7 @@ plugins:
   discourse_local_dates_enabled:
     default: true
     client: true
+    area: "localization"
   discourse_local_dates_default_formats:
     default: "LLL|LTS|LL|LLLL"
     client: true