WS-649: send CARTA URL to workspaces system

The mock messaging system being inoperable, these mods can be "tested" only by running CARTA Envoy on dev, which I will do following merge.

apps/web/src/app/workspaces/workspaces.component.html

@@ -11,6 +11,26 @@
         Launch null capability
       </button>
     </div>
+    <div class="d-flex px-2">
+      <button
+        type="button"
+        id="launchNullCapabilityCVBtn"
+        class="btn btn-secondary btn-lg"
+        (click)="nullCVButtonOnClick()"
+      >
+        Launch null at CV-NAASC
+      </button>
+    </div>
+    <div class="d-flex px-2">
+      <button
+        type="button"
+        id="launchNullCapabilityNMTBtn"
+        class="btn btn-secondary btn-lg"
+        (click)="nullNMTButtonOnClick()"
+      >
+        Launch null at NMT
+      </button>
+    </div>
   </div>
 </div>
 <div class="container border rounded py-3 my-3">