[ELO-189] refactor el reader/writer to a config based approach

[shrimalmadhur]

Fixes # .

What Changed?

• Add a new config based constructor for EL reader and writer
• Add nil checks so as to avoid nil pointer

Reviewer Checklist

• Code is well-documented
• Code adheres to Go naming conventions
• Code deprecates any old functionality before removing it

[samlaf]

Not super convinced by this. Honestly I think the better approach unfortunately is to fix the problem upstream, and to go fix the contracts so that they all point to each other and we only need to pass a single contract address, and we can recover all the other contracts from that one contract. Otherwise right now it's a bit confusing that I need to pass DM and AvsDirectory, but if I don't pass the DM, then I also don't get the slasher or SM, but the AvsDirectory is kind of its own little island.

[shrimalmadhur]

Not super convinced by this. Honestly I think the better approach unfortunately is to fix the problem upstream, and to go fix the contracts so that they all point to each other and we only need to pass a single contract address, and we can recover all the other contracts from that one contract. Otherwise right now it's a bit confusing that I need to pass DM and AvsDirectory, but if I don't pass the DM, then I also don't get the slasher or SM, but the AvsDirectory is kind of its own little island.

I 100p agree that's the better approach but I feel it's not going to happen soon and we will be stuck with breaking changes anytime we need to add some contracts. we should still go with this even though it's not ideal and make it flexible IMO to unblock. If at any point in future, contracts gets fixed and we have one master registry contract, we could just update the config to have that and deprecate other fields and then just use master contract.

[samlaf]

Should this just be called NewFromConfig? What's the rationale for using Build again?

[shrimalmadhur]

I don't have a strong pref. not sure why we used build in first place - maybe because it's building the bindings?

[shrimalmadhur]

I have a better names now - b9ba1be

elcontracts.NewReaderFromConfig

I will add similar in future

elcontracts.NewWriterFromConfig
avsregistry.NewReaderFromConfig
avsregistry.NewWriterFromConfig

wdyt?