feat: Derivation Test Fixtures

[refcell]

Description

Introduces the basic derivation test fixture format.

This should be everything we need to derive L2 Blocks from L1 while allowing for flexibility of reorgs.

{
	// List of l2 output roots to assert derivation against
	"l2OutputRoots": [ "0x...", ... ],
	// List of L1 blocks to derive from
	"l1Blocks": [
	  {
	    // A list of encoded blob data
	    "blobs": [ "0x...", ... ],
	    // A list of EIP-2718 encoded raw transactions
	    "transactions": [ "0x...", ... ],
	    // Since we know block numbers are sequential, the parent block is number - 1
	    // If the block number is the same as the last one in the array, we know the previous block in the array was re-org'd out.
	    "number": 1_000,
	    // Block timestamp is used in the derivation pipeline.
	    "timestamp": 1_000,
	    // ... any other metadata required for the pipeline
	  }
  ]

[0xKitsune]

Lgtm!