bug: diable haproxy zero copy forwarding

haproxy version 2.9.1 is consuming > 100% of cpu. the problem does not
happen in older versions. this commit disables the zero copy forwarding
as per workaround here:

haproxy/haproxy#2402 (comment)

we may want to enable this back in once it is fixed upstream.

pkg/internallb/haproxy.cfg

@@ -4,6 +4,7 @@
 #---------------------------------------------------------------------
 global
     log stdout format raw local0 notice
+    tune.disable-zero-copy-forwarding
     daemon
 
 #---------------------------------------------------------------------