dtl-modern v1.0.0

Reimplemented functionalities from dtl to dtl-modern (C++20)

• dtl_modern::diff
• dtl_modern::unidiff
• dtl_modern::edit_distance
• dtl_modern::merge
• dtl_modern::patch

New functionalities

• dtl_modern::ses_to_unidiff
• dtl_modern::extra::display
• dtl_modern::extra::display_pretty

Unimplemented functionalities

• unipatch
• trivial/unserious diff