Change schema.py to schema.yaml

[leszko]

Something to consider, not pushing on merging this one. We can simplify the lives of the potential pipeline developers by asking them to write schema.yaml instead of stream.py and then "magically" create the Pydantic class for them.

---

What pipeline developers need to write right now?

schema.py

from ..base_schema import BasePipelineConfig, ModeDefaults


class PassthroughConfig(BasePipelineConfig):
    pipeline_id = "passthrough"
    pipeline_name = "Passthrough"
    pipeline_description = "A pipeline that returns the input video without any processing that is useful for testing and debugging."

    supports_prompts = False

    modes = {"video": ModeDefaults(default=True)}

Something to consider (implemented in this PR, but needs closer look)

schema.yaml

pipeline_id: "passthrough"
pipeline_name: "Passthrough"
pipeline_description: "A pipeline that returns the input video without any processing that is useful for testing and debugging."

supports_prompts: false

modes:
  video:
    default: true