Extract vue-announcer and vue-skip-to styles (so that they're nt inline)

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/common.scss

@@ -3,6 +3,8 @@
 @import "~bulma";
 @import "~bulma-divider";
 @import "~buefy/src/scss/buefy";
+@import "styles/vue-announcer.scss";
+@import "styles/vue-skip-to.scss";
 
 // a {
 //   color: $violet-2;