Add an example for PRs that don't have anything to prove functionality

Some module submissions don't have a pcap, screenshot/video or anything
to prove the module is actually functional or not, because often due to
the author not having the test box anymore, or unable to share info
because of their NDA. We nee a way to prove the module runs by basically
simulating the vulnerable environment live, and this is the answer to that.

This test module is specifically for the cisco_asa_asdm.rb, but future
PRs with the same scenario can also borrow the same idea.
Oops, I didn't even catch this
Make msftidy happy
Land #2720, @wchen-r7's httpserver test module