Block number manipulation

[shunsukew]

Overview (What and Why)

Part of inkdevhub/swanky-node#49

swanky-node has manual block sealing feature via RPC engine_createBlock and engine_finalizeBlock.
Allowing users to forward/finalize blocks manually using swanky-cli command or library inside a script.
Similar to what hardhat has https://hardhat.org/hardhat-network-helpers/docs/reference#mine([blocks],-[options]).

• Seal block command & library exposed
• Finalize block command & library exposed
• (Multiple block sealing or sealing block up to block number X option. This might require swanky-node side development inkdevhub/swanky-node#49 (comment))

How

{Describe what needs to be done.}

• seal block command
• finalize block command

Definition of Done

{Write definition of done, how to verify}

• Unit test cases (delete if not applicable)
• Docs updated (delete if not applicable)
• PR approved and merged to master (delete if not applicable)

Open Issues and Blockers

{Dependencies issue or PR or some other blocker.}