feat(sidecar): add max_committed_gas_per_slot to sidecar Limits

[merklefruit]

Bolt sidecar operators should have a way to limit both the number and the gas amount used for commitments in a single slot.
For this, we already have the Limits config struct that can be extended.

These limits are enforced in the execution state validation pipeline here:

bolt/bolt-sidecar/src/state/execution.rs

Lines 204 to 210 in 7366aef

	if let Some(template) = self.get_block_template(target_slot) {
	if template.transactions_len() >= self.max_commitments_per_slot.get() {
	return Err(ValidationError::MaxCommitmentsReachedForSlot(
	self.slot,
	self.max_commitments_per_slot.get(),
	));
	}

it would also be ideal to place Limits inside the ExecutionState itself instead of copying the individual fields like this:

bolt/bolt-sidecar/src/state/execution.rs

Line 115 in 7366aef

max_commitments_per_slot: NonZero<usize>,