feat: remove existing feature before inserting new one

[rhizoome]

I know this is not the proper solution for #548 and I understand what should be done there. I am not sure if can do all of it, but I'll try.

But in the meantime, it still seems correct to not add a feature over and over again, even though backlinks should not do that in the first place.

feel free to ignore.

[rhizoome]

this is currently active on: https://publish.1042.ch/

[KosmosisDire]

Thanks, I'll look over this and decide if I feel like it works to implement it like this for now