Suggestion: Allow passing env.variables when calling `c2w-net`

[elpiel]

I know that you can pass env. variables when calling wasmtime and I saw that there's one env. variable passed to wasmtime by c2w-net but running your image might need some custom env. variables to be passed to it.

It would be great if there's an option in c2w-net to allow this.

[ktock]

SGTM