Add runj which is an experimental OCI runtime based on FreeBSD jails

Signed-off-by: Doug Rabson <dfr@rabson.org>

common/pkg/config/config.go

@@ -803,7 +803,7 @@ func (c *Config) Validate() error {
 
 func (c *EngineConfig) findRuntime() string {
 	// Search for crun first followed by runc, kata, runsc
-	for _, name := range []string{"crun", "runc", "kata", "runsc"} {
+	for _, name := range []string{"crun", "runc", "runj", "kata", "runsc"} {
 		for _, v := range c.OCIRuntimes[name] {
 			if _, err := os.Stat(v); err == nil {
 				return name

common/pkg/config/config_test.go

@@ -173,6 +173,9 @@ image_copy_tmp_dir="storage"`
 					"/bin/runc",
 					"/usr/lib/cri-o-runc/sbin/runc",
 				},
+				"runj": {
+					"/usr/local/bin/runj",
+				},
 				"crun": {
 					"/usr/bin/crun",
 					"/usr/local/bin/crun",

common/pkg/config/default.go

@@ -323,6 +323,9 @@ func defaultConfigFromMemory() (*EngineConfig, error) {
 			"/usr/lib/cri-o-runc/sbin/runc",
 			"/run/current-system/sw/bin/runc",
 		},
+		"runj": {
+			"/usr/local/bin/runj",
+		},
 		"kata": {
 			"/usr/bin/kata-runtime",
 			"/usr/sbin/kata-runtime",