[FEAT] Cohere LLM and embedder support (#1233)

* getChatCompletion working WIP streaming

* WIP

* working streaming WIP abort stream

* implement cohere embedder support

* remove inputType option from cohere embedder

* fix cohere LLM from not aborting stream when canceled by user

* Patch Cohere implemention

* add cohere to onboarding

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Co-authored-by: timothycarambat <rambat1010@gmail.com>