Update the documentation around Docker Compose

[nigellh]

Current Behavior

Please see https://github.com/DependencyTrack/dependency-track/issues/3938

Followed the instructions for starting a DT instance and it failed. This was due to docker-compose (with the '-') no longer being supported with the version of Docker I was using.

Proposed Behavior

Update the documentation to include this information and take the guidance from the above issue for installing Docker Compose as a plugin.

Checklist

• [X] I have read and understand the contributing guidelines
• [X] I have checked the existing issues for whether this enhancement was already requested