feat(derive): BatchProvider stage

[clabby]

Overview

As a part of the Holocene hardfork, the functionality of the BatchQueue is no longer needed after activation. This means we can replace the stage with a much more simplified version that only has to contend with single batches.

Similar to the pattern used to multiplex the ChannelAssembler and ChannelBank, we should multiplex the BatchQueue with a BatchSequencer stage upon Holocene activation.

Notably, this will require a few changes to the multiplexed_stage macro, to support additional generics as well as the ability to transfer more than just stage.prev over to the new stage.

When transmuting the BatchQueue into the BatchSequencer, batch_queue.l1_blocks must be preserved as it is passed over to the new stage.