Dockerfile to create a Faasd image.

While Faasd can't run in a container, this image can be imported into ignite which runs it in a firecracker microvm.

I need to do this because I need to run Faasd in the same machine as dockerized services and according to its documentation that shouldn't be done because both use incompatible versions of underlying dependencies.

Also in this way resource usage of Faasd and all "lambdas" in it is capped by the VM resources, and the rest of the system is sort-of-protected by the VM sandbox.