libwebsockets

ctest: sspc proxy minimal

CTest does not directly support daemon spawn as part of the test flow,
we have to specify it as a "fixture" dependency and then hack up daemonization
in a shellscript... this last part unfortunately limits its ability to run to
unix type platforms.

On those though, if the PROXY_API cmake option is enabled, the ctest flow will
spawn the proxy and run lws-minimal-secure-strems-client against it