Gloas state cache

[dapplion]

Issue Addressed

Allow the in-memory state cache to store both post-block states (payload status = empty) and post-payload states (payload status = full)

Proposed Changes

Add a new level to the state cache

- /// Map from block_root -> slot -> state_root.
+ /// Map from block_root -> slot -> payload_status -> state_root.

And force consumers to decide which payload_status they perfer when querying by block and slot

/// Filter for querying states by payload status.
pub enum PayloadStatusFilter {
    /// Only return the state where the execution payload was included.
    Full,
    /// Only return the state where the execution payload was not included.
    Empty,
    /// Return any state, preferring full to empty.
    Any,
}

The storage of HDiff buffers requires fixes, to be addressed in another PR