refactor wiki to vue sfc, fixes #4307

app/controllers/course/wiki.php

app/controllers/jsupdater.php

app/views/course/wiki/edit.php

lib/classes/VueApp.php

lib/models/WikiOnlineEditingUser.php

lib/models/WikiPage.php

resources/assets/javascripts/bootstrap/vue.js

resources/assets/javascripts/bootstrap/wiki.js

resources/assets/javascripts/entry-base.js

resources/assets/javascripts/init.js

resources/assets/javascripts/lib/jsupdater.js

resources/assets/javascripts/lib/wiki.js

resources/vue/components/WikiEditor.vue

resources/vue/components/WikiEditorOnlineUsers.vue