Ecosystem page for Apache Burr

[harishkesavarao]

[Short description explaining the high-level reason for the pull request]

Changes

Adds an ecosystem page for Apache Burr showcasing integrations, examples, and resources to help build better applications with Burr.

How I tested this

Built documentation locally:

Installing all project dependencies (pip install -e ".[docs]")
Running make html in the docs/ directory
Verifying the rendered HTML output

Notes

Checklist

• PR has an informative and human-readable title (this will be pulled into the release notes)
• Changes are limited to a single goal (no scope creep)
• Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future TODOs are captured in comments
• Project documentation has been updated if adding/changing functionality.

[harishkesavarao]

Implements item 2 mentioned in #589 (comment)