Removal of important historical content

[kamikazechaser]

I just noticed that a lot of important docs related to Celo's history were deleted in #2040. Notably Sep's video and the whole celo-economics-model.md that references the work of Charles Eisenstein file along with potentially other important files.

May I know why

1. This was done? Is that specific content being moved to the main website?
2. What steps are being taken to preserve such content and hyperlinks when migrating tech stacks for hosting docs?