Update func init to create test-compatible folder structure

[maiqbal11]

Currently, func init does not create a folder structure that clearly delineates test code from source code. Ideally, we would have the __app__ (function app folder) under a root folder which also contains a separate folder for tests. See Azure/azure-functions-python-worker#469 for more background on why this is needed. We imagine that the final structure would like what @brettcannon has here: https://github.com/microsoft/pvscbot/tree/azure-functions.

[ahmedelnably]

This is a P1 for Python but not a P1 for Core tools, hence removing the label

[kulkarnisonia16]

This is a P1 for Python post GA - and one of the two big changes we are tracking for November.

[empz]

This is causing a lot of headaches. Please try to update the CLI to generate the project with the recommended structure.
MicrosoftDocs/azure-docs#50089 (comment)

[maiqbal11]

@Hazhzeng @ankitkumarr