Integration with Broker-on-Mac

[rayluo]

This PR has been tested by an internal bug bash.

It will remain as a draft until the dependency PyMsalRuntime 0.14 is released on PyPI.
This PR depends on PyMsalRuntime 0.17 for its full support for SSH Cert and ROPC.

[rayluo]

FYI, those lines are the changes (or the lack thereof) of the parent_window_handle requirement between Windows and Mac.

The window handle is required on Windows. Such a decision was influenced by the MsalRuntime's desire to make window handle explicit (CC @MSamWils), and now on Mac this parameter remains required. (CC @kaisong1990 )

If the parameter remains required on Windows, do we want to keep it as required on Mac, or do we make it optional on Mac? Will the latter behavior - i.e. sometimes required, sometimes not - be confusing in itself?

Note: Regardless of MSAL's choice, downstream library can make different decision, such as choose to make this parameter optional, by using MSAL's predefined CONSOLE_WINDOW_HANDLE placeholder as a default value. (CC @xiangyan99 )

[xiangyan99]

Sorry, you mean it is required on Mac because it is required on Windows?

I am a little confused.

[rayluo]

Sorry, you mean it is required on Mac because it is required on Windows?

I am a little confused.

Put it this way. We speculate that one consistent API across platform would be ideal. Most Python scripts are console apps and they shall ideally be cross-platform. How do we want those app developers to write their source code?

1. app.acquire_token_interactive(
       ...,
       parent_window_handle=app.CONSOLE_WINDOW_HANDLE,  # Same placeholder across all platforms, even though it can be a no-op on some platforms
       ...)

2. if sys.platform == "win32":
       app.acquire_token_interactive(
           ...,
           parent_window_handle=app.CONSOLE_WINDOW_HANDLE,  # Required on Windows
       ...)
   else:
       app.acquire_token_interactive(
           ...,
           # No need to specify parent_window_handle at all
       ...)