Improved README, works with embedded Docker Compose

[alanhoyle]

This does two things:

1. Improves the README.md, adding and fixing links, and improving formatting
2. Recent versions of Docker Compose omit the docker-compose command and instead embed a new command in the main executable, run by running docker compose [...] This pull request allows GaPTools to work in either configuration of Docker.

[dimalvovs]

actually this worked for me for (for the standard examples) as opposed to the current master branch.

Apple M2 Pro
16 GB
K0H2WXWP1Q
14.3 (23D56)