feat: manage extensions navbar (#2121)

* feat: manage extensions navbar
create now `Manage` spacer in sidebar. and add manage extensions to it
closes #2088
* do not show when no exts
* update cn and jp i18n strings
* rename lnbits-admin-ui component to lnbits-manage, fix its behaviour
* i18n: add Korean language

---------

Co-authored-by: Pavol Rusnak <pavol@rusnak.io>
Co-authored-by: psychoet <125599543+psychoet@users.noreply.github.com>

lnbits/templates/base.html

@@ -261,10 +261,10 @@
       >
         <lnbits-wallet-list></lnbits-wallet-list>
 
-        <lnbits-admin-ui
-          v-if="'{{LNBITS_ADMIN_UI}}' == 'True'"
+        <lnbits-manage
+          :show-admin="'{{LNBITS_ADMIN_UI}}' == 'True'"
           :show-node="'{{LNBITS_NODE_UI}}' == 'True'"
-        ></lnbits-admin-ui>
+        ></lnbits-manage>
         <lnbits-extension-list class="q-pb-xl"></lnbits-extension-list>
       </q-drawer>
       {% endblock %} {% block page_container %}
@@ -352,7 +352,8 @@
         { value: 'pt', label: 'Português', display: '🇵🇹 PT' },
         { value: 'br', label: 'Português do Brasil', display: '🇧🇷 BR' },
         { value: 'cs', label: 'Česky', display: '🇨🇿 CS' },
-        { value: 'sk', label: 'Slovensky', display: '🇸🇰 SK' }
+        { value: 'sk', label: 'Slovensky', display: '🇸🇰 SK' },
+        { value: 'kr', label: '한국어', display: '🇰🇷 KR' }
       ]
     </script>
     {% block scripts %}{% endblock %}