docs(framework): Add documentation on how to register supernode to su…

[WilliamLindskog]

docs(supergrid): Add documentation on how to register supernode to supergrid

Issue

Description

There was no comprehensive documentation guide for users who want to register SuperNodes to the Flower SuperGrid using authentication keys. Users needed a step-by-step guide covering the entire process from prerequisites to troubleshooting.

Related issues/PRs

N/A - This is a new documentation contribution.

Proposal

Explanation

Added a new comprehensive how-to guide how-to-register-supernodes-on-supergrid.rst that provides:

• Complete prerequisites and setup instructions
• Step-by-step authentication key generation process
• Project configuration details
• SuperGrid login and verification procedures
• Detailed SuperNode registration workflow
• Docker-based SuperNode initialization instructions
• Federated task execution guidance
• Common troubleshooting scenarios and solutions
• Quick reference commands and checklist

The guide has been integrated into the deployment documentation section in deploy.rst, positioned logically after the existing SuperNode authentication guide.

Checklist

• [x] Implement proposed change
• [ ] Write tests (N/A for documentation)
• [x] Update documentation
• [x] Make CI checks pass
• [ ] Ping maintainers on Slack (channel #contributions)

Any other comments?

This documentation is based on the official SuperGrid registration workflow and provides users with all the information needed to successfully register and manage SuperNodes on the Flower SuperGrid platform.