Implement Kepler as serverless infrastructure

[wyc]

As a user, I want to deploy my own instance of Kepler conveniently across the growing number of "serverless" application hosting platforms so that I can enjoy Internet scale infra that I control at low cost with extremely low (or zero) maintenance overhead; "set it and forget it."

For example, I am interested in deploying to:

• AWS Lambda + Amazon S3 or (equivalent on Azure/GCP/etc.)
• Cloudflare Workers + KV Store (bundled/paid okay to get 50 ms of execution time instead of 5 ms)
• DigitalOcean App Platform + Spaces
• Netlify Functions + FaunaDB (or equivalent store)
• Vercel + FaunaDB (or equivalent store)

Furthermore, I should be able to access the instance with my favorite Web3 wallet. Content replication is not required for this phase.

[sbihel]

I think that would be a good thing to have. We should probably try to estimate at which amount of usage it is more cost effective.

Preliminary feasibility thoughts.

• With the on-demand loading it should be easy to disable at compile time so the startup time shouldn't be too high.
• For platforms which require their own HTTP server/interface it will require to completely separate the business logic from Rocket, which shouldn't be too hard but might be annoying.
• ipfs-embed will either need to be replaced or we'll have to add some kind of storage plugin to it (bring your own storage backend).
• The biggest hurdle might be the binary size. Currently a Linux binary in release mode is 23MB. Don't know how much of it is Rocket's.