Bugfix/51 selectionmodel fix (#60)

* bugfix for #51. ManagebusManagementThread now never accesses or changes the JAVAFX view-backing ObservableList but using a concurrenthasmap which drives the Tableview backing list with snapshots

* Extending work at #51 for not adding users on UM3 message

* Add interactive aircraft scatter hero effect

website/src/index.njk

@@ -2,9 +2,18 @@
 layout: base.njk
 title: KST4Contest – Contest-Optimized ON4KST Chat Client
 description: KST4Contest is a modern ON4KST chat client built for VHF, UHF and SHF contest operation.
+heroFx: true
 ---
 
 <section class="hero hero-split">
+
+  <canvas
+    class="hero-radio-fx"
+    data-hero-radio-fx
+    aria-hidden="true">
+  </canvas>
+
+  <div class="hero-fx-vignette" aria-hidden="true"></div>
   <div>
     <p class="badge">The contest-optimized ON4KST client</p>
     <h1>KST4Contest</h1>