Enhance GhostList with new iterator implementations and documentation updates (#24)

- Introduced `IntoIter` for consuming iteration over keys in MRU to LRU order, improving usability.
- Updated documentation to include detailed descriptions of new iterator types and their usage.
- Added `evict_lru` method documentation with examples, clarifying its behavior and expected outcomes.
- Enhanced operation table to reference methods directly, improving navigation and clarity for users.
- Implemented `PartialEq` and `Extend` traits for `GhostList`, allowing for easier comparisons and bulk insertions.

These changes aim to improve the API's usability and documentation clarity, aligning with the library's design goals.

Author: TKorr