Webatrice: Update nav (#4380)

* wip: subnav debug

* nav redesign

* remove unnecessary code

* remove subnav

* add leaveRoom button

Co-authored-by: Jeremy Letto <jeremy.letto@datasite.com>

webclient/src/index.css

@@ -40,6 +40,11 @@ b {
   font-weight: bold;
 }
 
+a {
+  color: inherit;
+  text-decoration: none;
+}
+
 .overflow-scroll {
   overflow-y: scroll; /* has to be scroll, not auto */
   -webkit-overflow-scrolling: touch;
@@ -54,4 +59,8 @@ b {
   text-overflow: ellipsis;
   white-space: nowrap;
   overflow: hidden;
+}
+
+.disabled-link {
+  pointer-events: none;
 }