Type checking for Python code

[fedimser]

This PR:

• Adds an option to run python static checks using build.py. Currently it only runs type checks using pyright, but more static checks (line length, linter, formatter) can be added here.
• Adds a new CI workflow that installs minimal requirements and runs the static checks.
• Fixes code to make static checks pass.

Notes:

• I only check Python code in source/qdk_package/qdk.
• Type checking requires different dependencies than tests, so I created a new file check_requirements.txt that includes minimal dependencies that are required to run static checks. This minimizes setup time for CI workflow.

The type checking can be done in multiple ways:

• pyright - runs pyright directly.
• ./build.py --check-py - recommended. This installs required dependencies and runs mypy, and doesn't do anything else. If this passes locally, it's guaranteed that it will pass on CI.
• python ./build.py --check-py --no-check-prereqs - like above, but skips checking prerequisites (like wasm) which are irrelevant for Python. This is used in the CI workflow.
• Run build.py in a way that includes building qdk and doesn't disable checks. This includes build.py --qdk and build.py with no arguments.

Missing checks (will be added in follow-up PRs):

• If we remove 6 excluded modules and specify "reportMissingParameterType": "error" and "typeCheckingMode": "strict" in pyrightconfig.json, we get 2745 errors. I plan to gradually fix them in a series of PRs.