Stub proposed APIs used by Python debugger

[msujew]

What it does

Closes #13881

Stubs the APIs listed in the package.json of the vscode-python-debugger plugin.

How to test

1. Download and install the Python extension suite (that includes the Python Debug extension)
2. Open a Python file.
3. There should be no notification that the extension crashes during startup.
4. You could also test that debugging works as expected for a simple python file.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[rschnekenbu]

That looks good to me, code wise and runtime wise. I could run the python debugger without any log messages.

[zoof]

Any idea when 1.52.0 is expected? I'm anxious to try Theia but as it stands now, it's unusable for me.

[msujew]

Hey @zoof, we release a new version of the framework on every last Thursday of the month, so likely on the 25th. You can expect a new version of the Theia IDE a few days after that.

[zoof]

Wonderful, thank you!