Include a debugging flow

[yoshuawuyts]

@squillace raised that he'd like to see this sample also include a debugging flow. For reference what we did in the Rust sample, bytecodealliance/sample-wasi-http-rust#55 and bytecodealliance/sample-wasi-http-rust#56 might be helpful.

[squillace]

Ok, have this running, at least partially. I'll push this for review, and ask others to see if GDB does work but something's wrong on my machine because it worked before!!!

[squillace]

#9