Teach our MiniHttpServer to better handle POST and PUT requests:
read the POST/PUT data too (not headers only), before replying
and flushing. The original comment says MiniHttpServer does
not support POST/PUT requests, it's not true anymore - we can
handle them (perhaps the simplest/shortest ones).
Task-number: QTBUG-62844
Change-Id: I80260f8ede1bb1b0b9d6042ecd59558bb7e9a998
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>