Add template to README

[konsumer]

Up to @twuky and @RobLoach, but I think it'd be cool to add my nice EXE project template to README.

Currently, the windows-build needs some work (in testing it says it's missing the DLL) which I am working on, but essentially it makes a single EXE out of a js file, using the new built-in SEA stuff. This helps with deployment, and the end-user should not need node or anything else installed. It even inlines the native raylib .node file, so it's all self-contained, and it builds faster than older methods that would build nodejs from scratch (it injects it into the system's existing node runtime, so no compile) which makes for much faster builds than nexe/pkg/boxednode/etc.

I setup nice CI for the template-project, so the user should only need to fork/edit main.js/push to get builds of their game, for very platform.