Move some DA checker functionality to `CustodyContext`

[eserilev]

Description

DataAvailabilityChecker: a cache to hold fully valid data that can't be imported to fork choice yet

CustodyContext: Contains all the information the node requires to calculate the number of blobs/columns to be custodied when checking for DA.

We have the following functions implemented for DataAvailabilityChecker that should be moved to CustodyContext

• blobs_required_for_epoch
• data_columns_required_for_block
• data_availability_boundary
• is_deneb (maybe we probably remove this completely, I don't think it's used anywhere)

This will help keep a better separation of concerns between the DataAvailabilityChecker and CustodyContext types

Additional Notes

As part of this refactor:

• DataAvailabilityChecker no longer needs a reference to slot clock, slot clock should move to CustodyContext. Move DA boundary checks to CustodyContext #8696
• RpcBlock::new should accept a CustodyContext as an argument instead of a DataAvailabilityChecker Move DA boundary checks to CustodyContext #8696
• Move AvailableBlock and AvailableBlockData from data_availability_checker.rs to block_verification_types.rs
• Delete enum DataSidecars and replace its usage with AvailableBlockData
• Explore passing RpcBlock::FullyAvailable to range and backfill sync
• Ensure all TODO(#8633) references in the codebase are resolved