seva-launcher: add support for docker compose v2

[yogeshhegde]

Docker compose v2 is built-in to the docker command and is not a script like docker compose v1 and the command invocation also changed from docker-compose to docker compose. Patch adds this feature so that seva-laucher can work with docker compose v2.

[jeevantelukula]

Also, I would suggest to return the args prefix from func prepare_compose() instead of just the binary name. Something like a small helper that prepends ["docker", "compose"] or ["docker-compose"] based on what was detected. During calling, we can just do exec.Command(composeArgs("-p", "seva-launcher", "up", "-d")...) uniformly without needing the if else checks in three places. Helps for future version changes in docker compose.