[Feature]: Add dockerfile to generation branch

[dicolanl]

Description of the new feature

Add the autorest for powershell docker file here in the generation branch under /src directory.

This will allow developers to open the docker file in VS Code and build and test via docker on any machine.

Proposed implementation details (optional)

No response

[dingmeng-xue]

@dicolanl , thanks for recommendation. Is it sufficient that we add docker file into azure-powershell repo? or do you mean we should publish docker file to MCR?

[dicolanl]

According this you could use a container registry.
it was easy to put the docker file there and tell vs code to open in container using the dockerfile.