[FEAT] Remove vectordb and embedder settings in onboarding flow (#1138)

* default to AnythingLLM embedder and LanceDB on onboarding for simpler setup

* remove unused onboarding flow components

* add text telling user settings can be reconfigured later

* remove space

* update copy
patch back-path navigation on onboarding

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