Participation panel revamp and fixes

Apollo is a pain in the ass with pagination & filters, so this removes
the tabs system and uses a <select> to filter instead

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

js/src/common.scss

@@ -10,7 +10,8 @@ a {
   &[href="#comments"],
   &.router-link-active,
   &.comment-link,
-  &.pagination-link {
+  &.pagination-link,
+  &.datepicker-cell {
     text-decoration: none;
   }
 }