As part of the Podman 6 release, we need to remove support for slirp4netns networking. Slirp4netns has been deprecated in favor of Pasta, which provides better performance and functionality for rootless networking.

This story involves:

• Removing slirp4netns code and dependencies from podman and c/common components
• Updating documentation to reflect the removal
• Ensuring migration path for users still using slirp4netns to Pasta
• Updating tests to remove slirp4netns-related test cases

Reference: Podman 6 High Level Design