Add the "curl" NSH command: a command-line HTTP client built on top of
the netutils webclient library. It implements a subset of the real curl
options: GET and POST (and other methods via -X), custom request headers
(-H), a raw request body (-d, including -d @file), multipart/form-data
file uploads (-F name=@file), saving the response body to a file (-o)
and verbose output (-v). HTTP only (no HTTPS).
Signed-off-by: Jorge Guzman <jorge.gzm@gmail.com>
