Add a new `maestro validate` ("dry run") command

Is your feature request related to a problem? Please describe. Facing issues in maintaining the sanity of flow files in the repo where multiple people are adding commits and there is no way to verify the sanity of the flow files since maestro does not have a build system that can verify for complication error.

Describe the solution you'd like In a CI system where multiple teams are adding tests in the same repo, it is essential to check the flow files' sanity and syntax in each merge request. A feature like checking the syntax, and file paths in the flow files of the entire workspace is necessary so that no bad flow files are added. A dry-run like feature can help validate the workspace and yaml flow files instead of running any.

Describe alternatives you've considered Currently, there is no way of validating the entire workspace.