Add Max Payload Size limit option (--max-payload-size)

This option excludes TCP packets with the data payload larger than
defined value from being copied by WinDivert driver to GoodbyeDPI.

As most of HTTP and TLS ClientHello packets are repatively small,
and file transfers are usually big and are sent/received using
the whole available MTU/MSS, we can just exclude them from
being processed by our userspace program to reduce unnecessary
CPU load.

README.md

@@ -58,6 +58,10 @@ Usage: goodbyedpi.exe [OPTION...]
  --reverse-frag           fragment (split) the packets just as --native-frag, but send them in the
                           reversed order. Works with the websites which could not handle segmented
                           HTTPS TLS ClientHello (because they receive the TCP flow "combined").
+ --max-payload [value]    packets with TCP payload data more than [value] won't be processed.
+                          Use this option to reduce CPU usage by skipping huge amount of data
+                          (like file transfers) in already established sessions.
+                          May skip some huge HTTP requests from being processed.
 
 
 LEGACY modesets: