Endpoint and button for "factory reset"

[pieroit]

Many people messes up with the embedders and LLMs, breaking the installation. Typical error comes from Qdrant:
TypeError: '>=' not supported between instances of 'ValueError' and 'int'

Let's have an endpoint to reset default llm and embedder (plugins should not be an issue).
Reset button could also be placed in admin settings for people not able to check out the terminal.