stages/selinux: add an selinux stage

This stage labels the target tree based on an SELinux policy already
installed in the target.

Signed-off-by: Tom Gundersen <teg@jklm.no>

samples/base-with-selinux.json

@@ -0,0 +1,23 @@
+{
+  "name": "base-with-selinux",
+  "stages": [
+    {
+      "name": "io.weldr.untree",
+      "options": {
+        "tree": "base"
+      }
+    },
+    {
+      "name": "io.weldr.selinux",
+      "options": {
+        "file_contexts": "etc/selinux/targeted/contexts/files/file_contexts"
+      }
+    }
+  ],
+  "assembler": {
+    "name": "io.weldr.tree",
+    "options": {
+      "tree": "base-with-selinux"
+    }
+  }
+}

samples/base.json

@@ -14,7 +14,8 @@
           }
         },
         "packages": [
-          "@Core"
+          "@Core",
+          "selinux-policy-targeted"
         ]
       }
     }