Move all core EE load balancing code to CE

This moves all files from:

ee/lib/gitlab/database/load_balancing* -> lib/gitlab/database
ee/spec/lib/gitlab/database/load_balancing* -> spec/lib/gitlab/database

config/initializers/load_balancing.rb

@@ -2,24 +2,22 @@
 
 # We need to run this initializer after migrations are done so it doesn't fail on CI
 
-Gitlab.ee do
-  if Gitlab::Database.cached_table_exists?('licenses')
-    if Gitlab::Database::LoadBalancing.enable?
-      Gitlab::Database.disable_prepared_statements
+if Gitlab::Database.cached_table_exists?('licenses')
+  if Gitlab::Database::LoadBalancing.enable?
+    Gitlab::Database.disable_prepared_statements
 
-      Gitlab::Application.configure do |config|
-        config.middleware.use(Gitlab::Database::LoadBalancing::RackMiddleware)
-      end
-
-      Gitlab::Database::LoadBalancing.configure_proxy
+    Gitlab::Application.configure do |config|
+      config.middleware.use(Gitlab::Database::LoadBalancing::RackMiddleware)
+    end
 
-      # This needs to be executed after fork of clustered processes
-      Gitlab::Cluster::LifecycleEvents.on_worker_start do
-        # Service discovery must be started after configuring the proxy, as service
-        # discovery depends on this.
-        Gitlab::Database::LoadBalancing.start_service_discovery
-      end
+    Gitlab::Database::LoadBalancing.configure_proxy
 
+    # This needs to be executed after fork of clustered processes
+    Gitlab::Cluster::LifecycleEvents.on_worker_start do
+      # Service discovery must be started after configuring the proxy, as service
+      # discovery depends on this.
+      Gitlab::Database::LoadBalancing.start_service_discovery
     end
+
   end
 end

ee/spec/lib/gitlab/database/load_balancing/srv_resolver_spec.rb → spec/lib/gitlab/database/load_balancing/srv_resolver_spec.rb

@@ -52,7 +52,7 @@ RSpec.describe Gitlab::Database::LoadBalancing::SrvResolver do
   end
 
   def dns_response_packet_from_fixture(fixture_name)
-    fixture         = File.read(Rails.root + "ee/spec/fixtures/dns/#{fixture_name}.json")
+    fixture         = File.read(Rails.root + "spec/fixtures/dns/#{fixture_name}.json")
     encoded_payload = Gitlab::Json.parse(fixture)['payload']
     payload         = Base64.decode64(encoded_payload)