Migration of Readme for autorest.python v5 based on autorest v3

General guidance

This applies globally to any readme.python.md that would want to be used with autorest.python v5

• Remove all python: section in readme.python.md
• Remove all ($python) tests from yaml code condition in readme.python.md

Multi-api

If your SDK is multi-api ready:

• Remove the complete after_scripts section under Python in the readme.md (impacts automation only)
• Move clear-output-folder:true inside the multiapi yaml block
• Add a multiapiscript section like this:

### Multi-api script

``` yaml $(multiapiscript)
output-folder: $(python-sdks-folder)/storage/azure-mgmt-storage/azure/mgmt/storage/
clear-output-folder: false
keep-version-file: true
perform-load: false

Complete example for Storage mgmt

https://github.com/Azure/azure-rest-api-specs/pull/8561