proxyAuth: allow protecting specific subpath

while I don't think this is useful for apps, it is useful for e2e test atleast

src/nginxconfig.ejs

@@ -238,11 +238,18 @@ server {
             index  index.html index.htm;
         }
 <% } else if ( endpoint === 'app' ) { %>
+    location = /appstatus.html {
+    }
+
     <% if (proxyAuth.enabled) { %>
+    location "<%= proxyAuth.path %>" {
         auth_request /proxy-auth;
         auth_request_set $auth_cookie $upstream_http_set_cookie;
         add_header Set-Cookie $auth_cookie;
         error_page 401 = @proxy-auth-login;
+
+        proxy_pass http://<%= ip %>:<%= port %>;
+    }
     <% } %>
 
     <% Object.keys(httpPaths).forEach(function (path) { -%>
@@ -251,9 +258,6 @@ server {
         }
     <% }); %>
 
-        location = /appstatus.html {
-        }
-
         proxy_pass http://<%= ip %>:<%= port %>;
 <% } else if ( endpoint === 'redirect' ) { %>
         # redirect everything to the app. this is temporary because there is no way