feat: allow to override the default dev api-key when running locally

[maelp]

I do a local dev setup, and I'd like to have the generated dev API key to be configurable, so that if I destroy my container and recreate it, I can keep the same, would it be possible to add (or document if it's already there) an option for this?

[maelp]

Saw this but it seems to be for an old version https://github.com/hyperdxio/hyperdx/issues/927

I guess it would be nice to add a DEV_INGESTION_API_KEY env var which overrides the default one when present