feat: add stacks_node_next_initiative_delay in devnet config

[hugocaillard]

This setting has been introduced in stacks-node for nakamoto.
We should experiment around having a default of value of 3 or 4 seconds. Lower values could allow to handle faster Bitcoin blocks but can also break the blockchain.
Maybe in the future we'll warn the users that can't put a value lower than X seconds, but that ok for now, we'll communicate about epoch 3.0 support as "beta"

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 16 lines in your changes missing coverage. Please review.

Files	Patch %	Lines
components/clarinet-files/src/network_manifest.rs	0.00%	6 Missing ⚠️
...omponents/stacks-network/src/chains_coordinator.rs	0.00%	6 Missing ⚠️
components/stacks-network/src/orchestrator.rs	0.00%	2 Missing ⚠️
components/clarinet-cli/src/generate/project.rs	0.00%	1 Missing ⚠️
components/stacks-network/src/ui/ui.rs	0.00%	1 Missing ⚠️

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