Contribute Maestro YAML schema to SchemaStore

[bartekpacia]

Initially discussed in #932. Contributions welcome!

Aim

• Show documentation on hover for command/command's arguments on mouse hover in VSCode (and other IDEs that work with SchemaStore)
• Provide some basic validation

Discussion

It would be cool to contribute a schema for Maestro to SchemaStore. From what I understand (may be wrong), once schema lands in SchemaStore, then the validation would work out-of-the-box for Maestro flows in VSCode.

By "Maestro flows" I mean:

• YAML files
• with names ending with _test.yaml or _flow.yaml`
• inside the .maestro directory (recursively)

Not sure if we can express conditions this specific.

It'd be really great if the schema could be auto-generated from Commands.kt, to reduce the maintenance burden.