Substrait ExecutionPlan Serialization

**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**
Serialize physical plans, AKA, `ExecutionPlan`s as Substrait plans.

**Describe the solution you'd like**
Expose Substrait consumers and producers for `ExecutionPlan` to allow for encoding to and decoding to / from Substrait.

**Describe alternatives you've considered**
Using LogicalPlans only.

首先定位 ExecutionPlan 的 Python bindings，以及現有的 Substrait 對 LogicalPlans 的支援。檢視目前的 plan consumers 和 producers 如何被公開，然後定義 physical plans 的編碼與解碼邊界。完成的標準是 ExecutionPlans 可以編碼為 Substrait plans，並從 Substrait plans 解碼。

由索引模型根據 Issue 內容生成。