Platform/pm 2138/add nginx to known proxies (#3012)

* Add nginx to known proxies

* Only add nginx proxy if standard self host deployment

* Style changes

* Add forwarded headers config to events server

* Add known proxy forwarding to missing services

* Catch DNS errors in adding nginx proxy

* Update src/SharedWeb/Utilities/ServiceCollectionExtensions.cs

Co-authored-by: Justin Baur <19896123+justindbaur@users.noreply.github.com>

---------

Co-authored-by: Justin Baur <19896123+justindbaur@users.noreply.github.com>

src/Events/Startup.cs

@@ -93,6 +93,12 @@ public class Startup
         // Add general security headers
         app.UseMiddleware<SecurityHeadersMiddleware>();
 
+        // Forwarding Headers
+        if (globalSettings.SelfHosted)
+        {
+            app.UseForwardedHeaders(globalSettings);
+        }
+
         if (env.IsDevelopment())
         {
             app.UseDeveloperExceptionPage();