Add config option for shared state dir

Signed-off-by: jcsiadal <jeremy.c.siadal@intel.com>

Changes default share to /srv/warewulf
Update specfile
Some changes to match Golang standards

internal/pkg/oci/cache.go

@@ -9,12 +9,6 @@ import (
 	"github.com/containers/image/v5/types"
 )
 
-const (
-	defaultCachePath = "/var/warewulf/container-cache/oci/"
-	blobPrefix       = "blobs"
-	rootfsPrefix     = "rootfs"
-)
-
 type CacheOpt func(*Cache) error
 
 func OptSetCachePath(path string) CacheOpt {

internal/pkg/oci/defaults.go

@@ -0,0 +1,11 @@
+package oci
+
+import 	"github.com/hpcng/warewulf/internal/pkg/warewulfconf"
+import  "path/filepath"
+
+var defaultCachePath = filepath.Join(warewulfconf.DataStore(), "/container-cache/oci/")
+
+const (
+	blobPrefix       = "blobs"
+	rootfsPrefix     = "rootfs"
+)