sequencer-relayer, conductor: EIP4844 support

[noot]

EIP4844 (proto-danksharding) is likely going to be shipped on eth mainnet around December afaik, it would be good to have support for this.

see https://eips.ethereum.org/EIPS/eip-4844#abstract for details on the EIP

implementation list:

• refactor our current DA read/write code to be a "DA trait` that can be implemented by both Celestia and Ethereum backends
• implement the Ethereum backend that uses EIP4844 blob transactions
• figure out how we will actually use multiple DA layers; should rollups be able to somehow configure which one (or both) they wish to use?

[steezeburger]

danksharding, nice

[joroshiba]

not planned atm, feasible for the future but not planned