Add receiver-ui route and cluster to YARP configuration

Added a new `receiver-ui` route under the `ReverseProxy:Routes`
section in `yarp.json` to match all paths for `GET` and `HEAD`
methods. The route is associated with the `receiver-ui` cluster
and has an `Order` value of 100.

Configured a new `receiver-ui` cluster under the
`ReverseProxy:Clusters` section with a single destination
pointing to `https://localhost:52936`. This enables reverse
proxying for the `receiver-ui` service.

EnvelopeGenerator.API/yarp.json

@@ -1,6 +1,14 @@
 {
   "ReverseProxy": {
     "Routes": {
+      "receiver-ui": {
+        "ClusterId": "receiver-ui",
+        "Order": 100,
+        "Match": {
+          "Path": "{**catch-all}",
+          "Methods": [ "GET", "HEAD" ]
+        }
+      },
       "auth-login": {
         "ClusterId": "auth-hub",
         "Match": {
@@ -24,6 +32,13 @@
       }
     },
     "Clusters": {
+      "receiver-ui": {
+        "Destinations": {
+          "primary": {
+            "Address": "https://localhost:52936"
+          }
+        }
+      },
       "auth-hub": {
         "Destinations": {
           "primary": {