feat: make setting bootnodes optional in prepare-configuration

[LGLO]

Description

This allows to run prepare-configuration without running generate-keys, making generation of keys optional.

Also, recommended order of running wizards has changed, moving setup-main-chain-state before create-chain-spec, although both can be run independently.

Checklist

• Commit sequence broadly makes sense and commits have useful messages.
• The size limit of 400 LOC isn't needlessly exceeded
• The PR refers to a JIRA ticket (if one exists)
• New tests are added if needed and existing tests are updated.
• New code is documented and existing documentation is updated.
• Relevant logging and metrics added
• Any changes are noted in the changelog.md for affected crate
• Self-reviewed the diff