Add debugpy entry point - #1639

Fixes #1613

• Added an entry point as documented at https://setuptools.pypa.io/en/latest/userguide/entry_point.html

Testing

Scenario 1 - Package is installed in active environment

Windows

1. I ran the internal debugpy pipeline, pointing the resources at my add_entry_point branch instead of main.
2. I downloaded the debugpy-1.8.2+12.g853cc05f-cp311-cp311-win_amd64.whl from https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=9942339&view=artifacts&pathAsName=false&type=publishedArtifacts
3. I installed the wheel by running python -m pip install --no-index --find-links . debugpy
4. I ran python -m debugpy -V to verify that it installed correctly.
5. Then I ran debugpy -V to verify that the entry point exists. The output was the same as the previous step, which proves the entry point works.
6. I also ran debugpy --listen 5678 "C:\Users\advolker\OneDrive - Microsoft\Desktop\pythonTest\infiniteLoop.py" and it ran correctly, which proves args are being passed along.

Linux (WSL)

1. Install WSL on a devbox using the docs at https://learn.microsoft.com/en-us/windows/wsl/install
2. Install python 3.10 using sudo apt install python3 python3-pip
3. Download the wheel from https://devdiv.visualstudio.com/_apis/resources/Containers/18694131/dist?itemPath=dist%2Fdebugpy-1.8.2%2B15.gaaab9932-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
4. Install the wheel using python3 -m pip install --no-index --find-links . debugpy
5. Add the bin directory to path like this: export PATH=$PATH:/home/advolker/.local/bin
6. Run debugpy -V and see that it works
7. I also ran debugpy --listen 5678 ./infiniteLoop.py and it worked.

Scenario 2 - Package is installed in random directory

Windows

1. I ran the internal debugpy pipeline, pointing the resources at my add_entry_point branch instead of main.
2. I downloaded the debugpy-1.8.2%2B15.gaaab9932-cp311-cp311-win_amd64.whl from https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=9950165&view=artifacts&pathAsName=false&type=publishedArtifacts
3. I installed the wheel by running python -m pip install -t .\temp --no-index --find-links . debugpy
4. I added C:\Users\advolker\OneDrive - Microsoft\Desktop\temp\bin to PATH, like this: SET PATH=%PATH%;C:\Users\advolker\OneDrive - Microsoft\Desktop\temp\bin
   1. This is the directory that contains the entry point (debugpy.exe on Windows)
5. I added C:\Users\advolker\OneDrive - Microsoft\Desktop\temp to PYTHONPATH, like this: SET PYTHONPATH=%PYTHONPATH%;C:\Users\advolker\OneDrive - Microsoft\Desktop\temp
   1. This is the root directory that the package was installed to
6. I ran debugpy -V to verify that the entry point works.
7. I also ran debugpy --listen 5678 "C:\Users\advolker\OneDrive - Microsoft\Desktop\pythonTest\infiniteLoop.py" and it ran correctly.

Linux (WSL)

1. Install WSL on a devbox using the docs at https://learn.microsoft.com/en-us/windows/wsl/install
2. Install python 3.10 using sudo apt install python3 python3-pip
3. Download the wheel from https://devdiv.visualstudio.com/_apis/resources/Containers/18694131/dist?itemPath=dist%2Fdebugpy-1.8.2%2B15.gaaab9932-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
4. Install the wheel using python3 -m pip install -t ./temp --no-index --find-links . debugpy
5. Add the bin directory to path like this: export PATH=$PATH:/home/advolker/temp/bin
6. Add the install directory to pythonpath, like this: export PYTHONPATH=$PYTHONPATH:/home/advolker/temp
7. Run debugpy -V and see that it works
8. I also ran debugpy --listen 5678 ./infiniteLoop.py and it worked.