feat: integrate w3up (user-controllable keys)

[akhileshthite]

w3up uses the power of UCANs and DIDs to create user controllable keys.

After this integration users will be able to:

• Control the data and keys
• Create a self-sovereign identity

Extension behaviour:
get user email -> run extension popup in the background (a separate window) -> user will verify the email -> user key is generated -> the rest UX is same

Learn more about w3up: https://blog.web3.storage/posts/w3up-beta-launch
Development: https://blog.web3.storage/posts/introducing-w3up
Example application: https://blog.web3.storage/posts/forever-note

w3up is currently in beta, they'll release this feature in Q1 2023 (soon). Upto 5Gib is free per user key (not sure).