Update site in preparation for Trustable launch
Preview of site here: https://reiterative.gitlab.io/test.trustable.io/
- Add About Us page and menu link, giving access to new hidden pages for Staff, Advisory Board and Company
- Add membership page and menu link
- Update Contributing page and add pages for workstreams
- Add footer menu with links to Legal placeholder pages, etc
- Add Trustable whitepaper to Reading page
- Add favicon for site
- Add banner image and various theme tweaks
- Update Makefile for latest version of pelican