[Web] Ship web app with IPFS

[guoliu]

Is your feature request related to a problem? Please describe.
After we moved to JAMstack, we can now utilize Next.js's static export functionality and ship the web app to users with IPFS. The web app will function as a SPA, and still fetch data from server.

• Configure Next.js for static export.
• Store and retrieve token from localStorage when transporting via IPFS, since cookie are restricted by domain.
• Solve CORS restriction for API calls when transporting via IPFS
• Pin webapp on IPFS network, self-hosted or via Pinata
• Update DNSLink of matters.news

Note on CORS restriction for API calls when transporting via IPFS:

Our server currently only allows localhost and *.matters.news domain for browser access, so browsers block API calls when initiated from IPFS public gateway. We can either relax the CORS restrictions on backend (security implications uncertain), or we can setup a lambda function that act as a proxy to our server (similar to this example). The later has the additional benefit of masking the traffic to our server.