allow fast server to be disabled by removing it from the config file

app/views/domains/_nav.html.haml

@@ -1,4 +1,5 @@
 .navBar.navBar--secondary
   %ul
     %li.navBar__item= link_to "Domains", organization_server_domains_path(organization, @server), :class => ['navBar__link', active_nav == :domains ? 'is-active' : '']
+    - if Postal.fast_server?
       %li.navBar__item= link_to "Tracking Domains", organization_server_track_domains_path(organization, @server), :class => ['navBar__link', active_nav == :track_domains ? 'is-active' : '']

lib/postal/config.rb

@@ -165,4 +165,8 @@ module Postal
     config.general&.anonymous_signup != false
   end
 
+  def self.fast_server?
+    !!self.config.fast_server
+  end
+
 end

lib/postal/message_db/message.rb

@@ -545,7 +545,7 @@ module Postal
       # Should this message be parsed?
       #
       def should_parse?
-        parsed? == false && headers['x-amp'] != 'skip'
+        parsed? == false && headers['x-amp'] != 'skip' && Postal.fast_server?
       end
 
       private