add sudo cowbuilder file

data/common.yaml

+---
+cowbuilder:
+  content:
+    - '# Members of the root group can run cowbuilder (needed for building Debian pacakges)'
+    - '%root ALL = NOPASSWD: /usr/sbin/cowbuilder'
+  priority: 50

hiera.yaml

+---
+version: 5
+defaults:  # Used for any hierarchy level that omits these keys.
+  datadir: data         # This path is relative to hiera.yaml's directory.
+  data_hash: yaml_data  # Use the built-in YAML backend.
+
+hierarchy:
+  - name: "Common data"
+    path: "common.yaml"
+