feat: Integrate functionary v1.4 and v2 models + add custom tokenizer support to Llama class (#1078)

* convert functionary-v1 chat handler to use hf autotokenizer

* add hf_tokenizer + inteegrate functionary-v1.4 prompt template

* integrate functionary v2 prompt template

* update readme

* set up parallel function calling wip

* set up parallel function calling

* Update README.md

* Update README.md

* refactor tokenizers

* include old functionary handler for backward compatibility

* add hf_tokenizer_path in server ModelSettings

* convert functionary-v1 chat handler to use hf autotokenizer

* add hf_tokenizer + inteegrate functionary-v1.4 prompt template

* integrate functionary v2 prompt template

* update readme

* set up parallel function calling wip

* resolve merge conflict

* Update README.md

* Update README.md

* refactor tokenizers

* include old functionary handler for backward compatibility

* add hf_tokenizer_path in server ModelSettings

* Cleanup PR, fix breaking changes

* Use hf_pretrained_model_name_or_path for tokenizer

* fix hf tokenizer in streaming

* update README

* refactor offset mapping

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Co-authored-by: Andrei <abetlen@gmail.com>