cluster script fix

[dusannosovic-ethernal]

Description

The current problem with cluster script is the ability to introduce relayer even if IBFT is active as a consensus mechanism. Relayer may be invoked only if PolyBFT is used.

This PR fix cluster script fixes the above mentioned problem:
Script will check what kind of consensus mechanism was invoked and consequently will introduce relayer or not.

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually

[vcastellm]

It's not clear what's the difference between both commands given the conditional, can we separate params composition to a variable and assign or leave the var empty given the conditions?

[Stefan-Ethernal]

Superseded by #1971.