Added context strings

Minor rewording

front/src/components/playlists/Form.vue

 <template>
   <form class="ui form" @submit.prevent="submit()">
-    <h4 v-if="title" class="ui header"><translate>Create a new playlist</translate></h4>
+    <h4 v-if="title" class="ui header"><translate :translate-context="'Popup/Playlist/Title/Verb'">Create a new playlist</translate></h4>
     <div v-if="success" class="ui positive message">
       <div class="header">
         <template v-if="playlist">
-          <translate>Playlist updated</translate>
+          <translate :translate-context="'Content/Playlist/Message'">Playlist updated</translate>
         </template>
         <template v-else>
-          <translate>Playlist created</translate>
+          <translate :translate-context="'Content/Playlist/Message'">Playlist created</translate>
         </template>
       </div>
     </div>
     <div v-if="errors.length > 0" class="ui negative message">
-      <div class="header"><translate>We cannot create the playlist</translate></div>
+      <div class="header"><translate :translate-context="'Content/Playlist/Error message.Title'">The playlist could not be created</translate></div>
       <ul class="list">
         <li v-for="error in errors">{{ error }}</li>
       </ul>
     </div>
     <div class="three fields">
       <div class="field">
-        <label><translate>Playlist name</translate></label>
+        <label><translate :translate-context="'Content/Playlist/Input.Label'">Playlist name</translate></label>
         <input name="name" v-model="name" required type="text" :placeholder="labels.placeholder" />
       </div>
       <div class="field">
-        <label><translate>Playlist visibility</translate></label>
+        <label><translate :translate-context="'Content/Playlist/Dropdown.Label'">Playlist visibility</translate></label>
         <select class="ui dropdown" v-model="privacyLevel">
           <option :value="c.value" v-for="c in privacyLevelChoices">{{ c.label }}</option>
         </select>
@@ -31,8 +31,8 @@
       <div class="field">
         <label>&nbsp;</label>
         <button :class="['ui', 'fluid', {'loading': isLoading}, 'button']" type="submit">
-          <template v-if="playlist"><translate>Update playlist</translate></template>
-          <template v-else><translate>Create playlist</translate></template>
+          <template v-if="playlist"><translate :translate-context="'Content/Playlist/Button.Label/Verb'">Update playlist</translate></template>
+          <template v-else><translate :translate-context="'Content/Playlist/Button.Label/Verb'">Create playlist</translate></template>
         </button>
       </div>
     </div>
@@ -71,22 +71,22 @@ export default {
   computed: {
     labels () {
       return {
-        placeholder: this.$gettext('My awesome playlist')
+        placeholder: this.$pgettext('Content/Playlist/Input.Placeholder', 'My awesome playlist')
       }
     },
     privacyLevelChoices: function () {
       return [
         {
           value: 'me',
-          label: this.$gettext('Nobody except me')
+          label: this.$pgettext('Content/Playlist/Dropdown', 'Nobody except me')
         },
         {
           value: 'instance',
-          label: this.$gettext('Everyone on this instance')
+          label: this.$pgettext('Content/Playlist/Dropdown', 'Everyone on this instance')
         },
         {
           value: 'everyone',
-          label: this.$gettext('Everyone')
+          label: this.$pgettext('Content/Playlist/Dropdown', 'Everyone')
         }
       ]
     }