Add embedding support for a provider that could be hosted locally (highly suggest BGE)

[veeceey]

Since the current supported providers for embeddings require an API call to open ai/ snowflake which costs money i would highly suggest to add support for embedding services that could be hosted locally like BGE. This would help save global resources and end-users' money.

[jennifermarsman]

Possible fix: PR #142

[tim13337]

@veeceey @jennifermarsman I made a concept how one could generally make the NLWeb ingestion chain more modular - would be great to get your feedback for that. Maybe it can be used to make the NLWeb ingestion more flexible.