Differentiate chain-id and supernet-id

[goran-ethernal]

Description

Through this PR we are differentiating chain-id from supernet-id in the genesis file.

Before, chain-id was equal to supernet-id provided by StakeManager when supernet was registered to it in the rootchain deploy command.

Now genesis file will have both chain-id and supernet-id values, where supernet-id will be in the polybftconfig struct in genesis.
chain-id flag in genesis command stays, so that the users can use a custom chain-id for their supernet,

NOTE: supernet-id is not a flag in genesis command, but a value in the genesis file which is populated by the rootchain deploy command when supernet is registered to StakeManager contract.

supernet-id is used for staking, since validators need to provide the supernet id when calling the stakeFor function on StakeManager so that contract knows on which supernet validator is trying to stake.

Commands changed in this PR:

• stake command - flag chain-id is renamed to supernet-id.

Tagging @DannyS03 to update the docs.

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]

Late LGTM