Distribute live2d overlay as executable and remove electron dependency

[endernoke]

Describe the bug
Currently you need electron installed (globally) to be able to run the Live2D avatar overlay, which depends on node and npm/npx, so users might need to go through the installation of a lot of packages if they aren't already a nodejs dev.

Also the installation process is only mentioned in the README which few people will pay attention to.

To Reproduce

1. Uninstall npm
2. Install cheerleader extension
3. Overlay fails to launch (Error: the task 'cheerleader: Cheerleader Overlay' neither specifies a command nor a dependsOn property.)

Expected behavior
For better UX, users should be able to install and launch cheerleader directly without any additional setup, or at least have a notification or popup to inform them of the electron dependency.

So we might want to bundle the overlay app into an executable, tho this might need some effort to work since calling external executables from an vscode extension is rare.

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
Add any other context about the problem here.