Update some components to use i18n function, update en & zh-CN translation

src/pages/AddStatusPage.vue

@@ -21,7 +21,9 @@
                         <div class="form-text">
                             <ul>
                                 <li>{{ $t("Accept characters:") }} <mark>a-z</mark> <mark>0-9</mark> <mark>-</mark></li>
-                                <li>{{ $t("Start or end with") }} <mark>a-z</mark> <mark>0-9</mark> only</li>
+                                <i18n-t tag="li" keypath="startOrEndWithOnly">
+                                    <mark>a-z</mark> <mark>0-9</mark>
+                                </i18n-t>
                                 <li>{{ $t("No consecutive dashes") }} <mark>--</mark></li>
                             </ul>
                         </div>

src/pages/ManageStatusPage.vue

@@ -12,7 +12,7 @@
             <div class="shadow-box">
                 <template v-if="$root.statusPageListLoaded">
                     <span v-if="Object.keys($root.statusPageList).length === 0" class="d-flex align-items-center justify-content-center my-3">
-                        No status pages
+                        {{ $t("No status pages") }}
                     </span>
 
                     <!-- use <a> instead of <router-link>, because the heartbeat won't load. -->