Save some context when using functions

[tarasglek]

With functions it's easy to blow past all context limits. Atm i delete messages one by one once i feel I have too many.

1. Add "Delete Messages After This"
2. should be able to choose to not send function output to gpt when sending next message eg: [x] never send

[humphd]

1. Add "Delete Messages After This"

Created https://github.com/tarasglek/chatcraft.org/pull/211 to fix this part.