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: {Packaging} Clean up snap file #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: Dataprotection ModuleNotFoundError 'azure.mgmt.resourcegraph' azure-cli-extensions#4562 (comment))
• build_scripts/windows/scripts/setup_msi_test.ps1 and build_scripts/windows/scripts/test_msi_package.py
• Dockerfile.spot and Dockerfile.nanoserver {Misc.} Remove unused dockerfile #29195

[yonzhan]

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