Update for README & .repos & other documentations

[Hermanye996]

Proposed changes

I have adjusted the .repo configuration and deleted documentation and license related to Champ. I have also reformed README.md for the new navigation and bringup user guide.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Code refactor (non-breaking change which refactors the code)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation update only
• [X] Documentation update and .repo configuration adjustment.

Testing and Verification

To verify these changes, I performed the following tests:

1. check the new README.
2. check the .repo file.
3. check other documentation's modifications.

Test Configuration

Mini Pupper Version
Mini Pupper

Raspberry Pi OS + ROS version
Ubuntu 22.04, ROS 2 Humble

PC OS + ROS version
Ubuntu 22.04, ROS 2 Humble

Checklist

• [X] I have read the CONTRIBUTING guidelines.
• [X] I have checked to ensure there aren't other open Pull Requests for the same change.