Improve grep system

[kqito]

This PR enhances the grep system with the following changes:

• Parallel Processing: Integrated the rayon crate for parallel processing to improve performance.
• File Type Filtering: Added the -t/--filetype option to filter results by file type (file, directory, symlink).
• Code Simplification: Removed the --unique option and implemented automatic deduplication.
• Cleaner Path Matching: Improved path handling by omiting ./ prefixes and enhanced regex matching for paths and line/column numbers.