Use iterators instead of lists

[Gadiguibou]

Perform copy detection using iterators instead of lists and concatenated strings to avoid unnecessary memory allocations for large projects.

• Benchmark baseline performance of the current tool using a test dataset and the hyperfine command-line tool
• Change some of the key methods to take in Iterators (using a generic type) instead of Vecs. The goal is to lazily process as much as possible and avoid copies.
• Benchmark it again to see if there was a performance improvement.
• Open a PR 🚀!