Create documentation for partners on generating management SDKs using MPG

[ArthurMa1978]

We plan to ship our MPG to customers, allowing them to generate the SDK independently.
Therefore, we need to create documentation that explains how to generate the Azure mgmt. SDK using MPG.
Please refer to the .NET generation documentation for guidance.

[qiaozha]

we should figure out what kind of emitter options is required for pipeline validation.

[qiaozha]

what about less configuration?

[qiaozha]

hold on as there's some further discussion about whether to introduce docker for it.