Allow configuring LiveBuilder durations

[liamaharon]

rbuilder/crates/rbuilder/src/live_builder/mod.rs

Lines 40 to 46 in 469f1dc

	/// Time the proposer have to propose a block from the beginning of the slot (https://www.paradigm.xyz/2023/04/mev-boost-ethereum-consensus Slot anatomy)
	const SLOT_PROPOSAL_DURATION: std::time::Duration = Duration::from_secs(4);
	/// Delta from slot time to get_header dead line. If we can't get the block header before slot_time + BLOCK_HEADER_DEAD_LINE_DELTA we cancel the slot.
	/// Careful: It's signed and usually negative since we need de header BEFORE the slot time.
	const BLOCK_HEADER_DEAD_LINE_DELTA: time::Duration = time::Duration::milliseconds(-2500);
	/// Polling period while trying to get a block header
	const GET_BLOCK_HEADER_PERIOD: time::Duration = time::Duration::milliseconds(250);

are hard coded assuming mainnet block times, they need to be adjusted for shorter L2 block time intervals.

[ZanCorDX]

It's definitely useful to have this configurable for L2 but I would not go all the way to the config file. SLOT_PROPOSAL_DURATION is part of the protocol I wouldn't let the user change this value.