Add documentation for compose support in `--help` and man pages

[abhibongale]

#1839 was closed recently and it was noted that compose functionality which is now supported lacks documentation. It should document the feature in the ramalama server --help and in the associated man pages.

This will allow user to understand how to use the compose feature with the serve command.

Accpetance Criteria:

• Document in the man page detailing how compose is used with serve with relevant flags and scenario.
• Ensure that ramalama server --help mentions compose support explicitly.

Additional Context:

• Lack fo documentation was mentioned in the Add Docker Compose generator #1839.
• Feature has poor visibility due to lack of documentation.