Update chat docs (#450)

* fix(chat): add assistantId to step 3 of quickstart

* feat: break down chat doc into 4 separate docs

* chore: update navigation to include 4 chat docs

* fix: update navigation icons

* chore: update chat docs, delete old doc

* feat: update examples to use typescript, be more concise, remove unnecesary text

* fix: links for next steps

* fix: chat slugs

* fix: broken links in next steps

* chore(openai-compatibility): remove unnecessary copy

* fix: broken prereq links

* chore: cleanup comments, expand examples

Author: goosewin