[#844] Add `withChainId` and `withMinBlockTime`

Description

Problem: Cleveland currently has two functions for setting the emulator's initial state: withInitialNow and withInitialLevel. We should also have a way of setting the emulator's constant variables, MINIMAL_BLOCK_DELAY and CHAIN_ID.

Solution: Add withMinBlockTime and withChainId.

Related issue(s)

Resolves #844 (closed)

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