Remove `datafusion.proto` and use the `datafusion-proto` api for logical plan serde

[andygrove]

Is your feature request related to a problem or challenge? Please describe what you are trying to do. This repo contains an out-of-date copy of the datafusion.proto from the arrow-datafusion repo

Describe the solution you'd like Once https://github.com/apache/arrow-datafusion/issues/2630 is implemented, we should leverage this crate for serializing logical plans.

Describe alternatives you've considered None

Additional context None