RFC idea: Parachain management & recovery parachain

[xlc]

Fellowup of #14

Related discussions:

https://forum.polkadot.network/t/how-to-recover-a-parachain/673
https://forum.polkadot.network/t/polkadot-summit-ecosystem-technical-fellowship-workshop-notes/3269

We want a system parachain that's able to help other parachains to manage the parachain wasm/state.

We need to figure out how much power we want to give to the new ecosystem fellowship collective.

I will image parachain should be able to opt-in/out various ways of updating wasm. Including from para manager, or by the ecosystem fellowship, or by some custom origin which maybe controlled by some other parachains.