chore: rename repo from Dragonfly2 to dragonfly

[gaius-qi]

Description

This pull request includes several changes to update references from Dragonfly2 to dragonfly across multiple documentation files and code comments. The changes ensure consistency and accuracy in the project references.

Documentation updates:

• ADOPTERS.md: Updated the link to Dragonfly 2.0 repository.
• CONTRIBUTING.md: Updated multiple links and repository references from Dragonfly2 to dragonfly for forking, cloning, setting remote, and branch definitions. [1] [2] [3] [4] [5]
• README.md: Updated badges and discussion links to point to the new repository. [1] [2]
• build/images/base/README.md: Updated the git clone command to use the new repository URL.

Code comments updates:

• client/daemon/transport/transport.go: Updated issue reference in a comment.
• pkg/net/ip/ipv4.go: Updated pull request reference in a comment.

Other documentation updates:

• build/package/docs/dfcache/dfcache.1, dfcache.md, dfget.1, dfget.1.md, dfstore/dfstore.1, dfstore.md: Updated GitHub Issues references to the new repository. [1] [2] [3] [4] [5] [6]

Related Issue

#3714

Motivation and Context

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[chlins]

lgtm