Lm-format-enforcer

- Added official vLLM integration that doesn't require monkey patching.

- JSON Schema : Supports string min/max length limitation

- Community PR: Fixed SequenceParser bug

- Added haystack integration

- Fixed llama.cpp integration to be able to generate unicode characters in json freetext fields
- Fixed unescaped newlines being allowed in json freetext fields

- RegexParser and JsonSchemaParser can now output all of the characters that exist in the tokenzier
- Added "Known issues and limitations" section to the README
- Fixed a bug in JsonSchemaParser where sometimes illegal commas were allowed