resources: Add new hostname resource

This resource allows to set and watch the hostname on a system.

Signed-off-by: Vinzenz Feenstra <vfeenstr@redhat.com>

examples/hostname.yml

@@ -0,0 +1,7 @@
+---
+graph: mygraph
+resources:
+  hostname:
+    - name: Hostname Watcher @ TestHost
+      hostname: test.hostname.example.com
+edges: []