Timeout caused by large body request

[quertenmont]

Hello,

I am frequently working with request with a large body and silk request detail page is often timing out because of the CURL and Client encoding of those large requests.
I made a PR where CURL and Client command generations are not called when the request body is too big (20K characters).
Feel free to add a configuration parameter to customize this threshold.

Would be nice if you could merge this change

#768

Thanks in advance,
Loic