Add Documentation on UV and Tool Usage

[JennyPng]

Description

#42858

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[scbedd]

I've got one last piece of feedback that I'd like you to incorporate...but if you merged this as-is I wouldn't block, so approving!

[scbedd]

Oh and add azpysdk to the dictionary of known words in .vscode/cspell.json.

[Copilot]

Pull Request Overview

This PR introduces comprehensive documentation for the Azure Python SDK's new tool usage system, specifically focusing on the migration from tox-based checks to the new azpysdk entrypoint. The documentation provides developers with clear guidance on using modern tools like UV for faster package management and development workflows.

Key Changes

• Adds a complete tool usage guide covering the new azpysdk entrypoint and available tools
• Updates CONTRIBUTING.md to include UV as a recommended package manager alongside existing tools
• Adds spell-check dictionary entry for the new azpysdk term

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
doc/tool_usage_guide.md	New comprehensive guide covering azpysdk tools, setup procedures, and usage patterns
CONTRIBUTING.md	Updated tools overview section to include UV package manager documentation
.vscode/cspell.json	Added "azpysdk" to spell-check dictionary to prevent false positives