Share Docker Images as Executables

Introducing `docker2exe`, a tool that converts Docker images into self-contained executables for easy sharing! It's cross-platform compatible, requiring Docker, GoLang, and gzip on the build machine, and only Docker on the execution machine. Usage is straightforward: `docker2exe --name alpine --image alpine:3.9` creates an executable. It also supports embedding the image within the executable, automatically pulling and running it if the image isn't found on the target machine. This is especially useful for smaller images. The resulting executables are typically under 10MB.