podman load: support downloading files

Support downloading files, for instance via
`podman load -i server.com/image.tar`.  The specified URL is downloaded
in the frontend and stored as a temp file that gets passed down to the
backend.

Also vendor in c/common@main to use the new `pkg/download`.

Fixes: #11970
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/containers/common/pkg/config/config.go

@@ -461,6 +461,10 @@ type SetOptions struct {
 
 // NetworkConfig represents the "network" TOML config table
 type NetworkConfig struct {
+	// NetworkBackend determines what backend should be used for Podman's
+	// networking.
+	NetworkBackend string `toml:"network_backend,omitempty"`
+
 	// CNIPluginDirs is where CNI plugin binaries are stored.
 	CNIPluginDirs []string `toml:"cni_plugin_dirs,omitempty"`
 

vendor/github.com/containers/common/pkg/config/containers.conf

@@ -260,6 +260,10 @@ default_sysctls = [
 
 [network]
 
+# Network backend to use. Default "CNI".
+#
+#network_backend = "cni"
+
 # Path to directory where CNI plugin binaries are located.
 #
 #cni_plugin_dirs = [

vendor/github.com/containers/common/pkg/config/default.go

@@ -201,6 +201,7 @@ func DefaultConfig() (*Config, error) {
 			UserNSSize:         DefaultUserNSSize,
 		},
 		Network: NetworkConfig{
+			NetworkBackend:   "cni",
 			DefaultNetwork:   "podman",
 			DefaultSubnet:    DefaultSubnet,
 			NetworkConfigDir: cniConfig,