Currently, checkpointctl shows IP address information for checkpoints created
with CRI-O but not with Podman. For Podman checkpoints, this information is
stored in network.status in JSON format.

This commit adds support for extracting and displaying network information
from Podman container checkpoints by:
- Adding network.status file parsing functionality
- Displaying IP and MAC address information in checkpoint show output
- Adding test coverage for network information parsing
- Maintaining compatibility with existing checkpoint formats
- Updated import references from lib to metadata for consistency

Testing Results:
1. Test Environment:
   - Container: nginx (docker.io/library/nginx:latest)
   - Container ID: 4cf1a79a043a
   - Runtime: crun

2. Verification:
   - Successfully extracts network.status from checkpoint
   - Correctly displays IP address (10.88.0.2/16)
   - Correctly displays MAC address (c2:10:ff:79:ea:72)
   - Maintains all existing checkpoint information

Fixes: checkpoint-restore#132
Signed-off-by: deveshgoyal1000 <[email protected]>

Currently, checkpointctl shows IP address information for checkpoints
created with CRI-O but not with Podman. This patch adds support for
extracting and displaying network information from Podman container
checkpoints.

The network information is stored in network.status file in JSON format:
{
  podman: {
    interfaces: {
      eth0: {
        subnets: [{
          ipnet: 10.88.0.9/16,
          gateway: 10.88.0.1
        }],
        mac_address: f2:99:8d:fb:5a:57
      }
    }
  }
}

Implementation details:
- Extract network.status file from checkpoint archive
- Parse JSON content to get IP and MAC address information
- Add network information columns to output table
- Display IP address and MAC address for Podman containers
- Add test coverage for network information parsing
- Handle network information extraction errors gracefully

This enables users to see network configuration for Podman
checkpoints, providing parity with CRI-O checkpoint display.

Fixes: checkpoint-restore#132
Signed-off-by: deveshgoyal1000 <[email protected]>

Currently, checkpointctl shows IP address information for checkpoints
created with CRI-O but not with Podman. This patch adds support for
extracting and displaying network information from Podman container
checkpoints.

The network information is stored in network.status file in JSON format:
{
  podman: {
    interfaces: {
      eth0: {
        subnets: [{
          ipnet: 10.88.0.9/16,
          gateway: 10.88.0.1
        }],
        mac_address: f2:99:8d:fb:5a:57
      }
    }
  }
}

Implementation details:
- Extract network.status file from checkpoint archive
- Parse JSON content to get IP and MAC address information
- Add network information columns to output table
- Display IP address and MAC address for Podman containers
- Add test coverage for network information parsing
- Handle network information extraction errors gracefully

Files changed:
- internal/container.go: Add network info display
- internal/podman_network.go: Network info extraction
- internal/podman_network_test.go: Test coverage

Testing:
- All Go unit tests pass
- All 61 BATS integration tests pass
- Container checkpoint tests pass
- Network information display verified in EC2

This enables users to see network configuration for Podman
checkpoints, providing parity with CRI-O checkpoint display.

Fixes: checkpoint-restore#132
Signed-off-by: deveshgoyal1000 <[email protected]>