Demo & Docs cleanup

[lukemarsden]

Goal: website is compelling and everything on it is correct and works

Demo

• [x] Manually test init, verify, dataset, multi stage roadsigns demo
• [x] Do a release
• [x] Record demo video
• [x] Put demo video on homepage

Docs updates

• [x] Go through dev build updating/fixing/deleting as appropriate
• [x] https://sameproject.ml/getting-started/importing-packages/ is probably not relevant now, replace with new page about how same verify + requirements.txt support works
• [x] Add same init page
• [x] Add same dataset page with IPFS example
• [x] Do a full pass through docs fixing anything that seems broken or adding anything that seems missing

GitHub readme

• [x] Properly documented Github README