[linter] don't allow people to alias

[iscai-msft]

When SDK writers alias model names to rename the generated code, i.e. from ._generated import AuthenticationTypeEnum as DatasourceAuthenticationType, this breaks apiview, sphinx documentation, and does not show up well for end users

We should look through the __init__ files and raise an error if the aliased name is included in the __all__ (it's ok if internal models are aliased) and ensure there is no x as x importing.

We want to see how many aliasing issues we are running into.

In terms of mitigation for aliasing cases (thanks @lmazuel ):

1. If handwritten code: don't do it, you don't need it
2. If rename generated: use directive
3. Else: talk to Johan/Anna

[lmazuel]

There is many solutions to avoid this problem:

• Create an handcrafted class with from_generated/to_generated
• Rename the Swagger. Even a directive if necessary, so the name is right.
• Inherit the internal class:

class NewName(OldName):
   pass

But the nbame alias is confusing for all automation, since this is a local name alias in the SDK code, and doesn't reflect nicely in outside code.