Add Dappnode documentation to the existing quick start guide

[boulder225]

🎯 Problem to be solved

Add Dappnode documentation to the existing quick start guide for solo and group flows. https://docs.obol.tech/docs/start/quickstart_group

🛠️ Proposed solution

• Review the existing quick start guide and identify the appropriate sections for adding Dappnode documentation
• Consider using tabs or nested tabs to separate the command line and Dappnode flows
• Use the Dappnode quick start guide created by @alansunny3 as a reference
• Ensure that the documentation covers steps such as installing the package, copying ENRs, and any other necessary steps