Add tool usage scenarios

[harp-intel]

This pull request updates the tools/README.md file to provide a more comprehensive, user-friendly, and decision-oriented overview of available performance monitoring and profiling tools. The documentation now includes clearer tool descriptions, best-use scenarios, and a decision guide to help users select the right tool for their needs.

Documentation improvements:

• Expanded each tool's description to clarify its primary use cases, advantages, and best-fit scenarios.
• Added a "Choosing the Right Tool" section with a decision-tree format to help users quickly identify which tool to use based on their performance analysis goals.
• Grouped tools by typical user needs (e.g., quick assessment, deep optimization, cluster analysis, memory/bandwidth issues, GPU optimization, power monitoring, call stack visualization).
• Improved readability with thematic headings, bullet points, and emoji highlights for best-use cases and key advantages.

[jasukhar]

i think links should be moved to the top - maybe even incorporated to sections about tools.

[jasukhar]

it might be helpful to add 1-2 popular analysis tools like linux perf and in what scenarios they might be useful