Removed unused files in repo

[bebound]

There are some unused files in this repo, which may introduce unnecessary cognitive load. I create this issue to track these files and plan to remove them one by one. Here are the candidates:

• [ ] snap file: https://github.com/Azure/azure-cli/pull/27165
• [ ] /tools: this is an ancient version of azdev, but some scripts still uses it. It can be replaced with azdev_setup.yml
• [ ] azure-cli2017.pyproj: This file is used by visual studio to mark repo as Python project.
• [ ] scripts/release/debian/Dockerfile: not used
• [ ] scripts/release/homebrew/pipeline.sh: the logic is moved to azure-pipeline.yml, upload.sh: not used
• [ ] azure/cli/command_modules/xray-0.4.2.tgz
• [ ] __init__.py files: Not required in Modern PEP420. (These files also make it impossible to load azure-xx dependency in extensions: https://github.com/Azure/azure-cli-extensions/issues/4562#issuecomment-1780460073)
• [ ] build_scripts/windows/scripts/setup_msi_test.ps1 and build_scripts/windows/scripts/test_msi_package.py
• [ ] Dockerfile.spot and Dockerfile.nanoserver #29195

[yonzhan]

Thank you for opening this issue, we will look into it.