Context

We will remove sudo on Litmus soon #775
For local dev network it's still beneficial to have sudo.

We'll switch to rococo for the default development environment (an alternative is keeping sudo pallet on Litmus and using featured compilation but switching to rococo is easier), things to check:

• rococo chain-spec and parachain-launch works
• double-check the environment is close to Litmus (as possible)
• adjust README
• deploy rococo-chain spec in staging

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