feat: add third party licenses lists

[jackye1995]

The files are generated with make licenses, currently expected to run manually. In the future, some automations could be built.

[github-actions]

PR Review: feat: add third party licenses lists

This PR adds license generation tooling for Rust, Python, and Java dependencies. Overall this is a good addition for license compliance.

P1 Issues

1. Incorrect intro text in the generated HTML template (about.hbs line 42):

   <p>This page lists the licenses of the projects used in cargo-about.</p>

   This should reference Lance, not cargo-about. Consider changing to:

   <p>This page lists the licenses of the third-party projects used in Lance.</p>

2. Large generated files checked into git: The three RUST_THIRD_PARTY_LICENSES.html files add ~47K lines of generated HTML to the repository. Consider:

   • Adding these to .gitignore and generating them only during release/packaging
   • Or documenting in the PR description why these need to be version-controlled

Minor Observations (non-blocking)

• The PYTHON_THIRD_PARTY_LICENSES.md lists some packages with UNKNOWN license (e.g., arro3-core, geoarrow-rust-core). This is informational - these may need manual verification.
• The Makefile assumes uv is installed for Python license generation - this is reasonable given the project setup.