Fix i18n

Missing webhook json description
Ajust Telegram context-based sentence, (also changed translated language files)
Missing primary base url label
Wrong PromoSMS i18n
Missing Octopush legacy hint
Missing Matrix i18n
Missing push url i18n

src/components/notifications/Webhook.vue

@@ -16,7 +16,7 @@
         </select>
 
         <div class="form-text">
-            <p>"application/json" is good for any modern http servers such as express.js</p>
+            <p>{{ $t("webhookJsonDesc", ["\"application/json\""]) }}</p>
             <i18n-t tag="p" keypath="webhookFormDataDesc">
                 <template #multipart>"multipart/form-data"</template>
                 <template #decodeFunction>