fix: ignore vars/network.yml, because it has to be provided separately for...

fix: ignore vars/network.yml, because it has to be provided separately for each install run anyway and isn't suitable for version control

.gitignore

@@ -77,3 +77,11 @@ tags
 #########
 
 build/
+
+# temporary files #
+###################
+
+# A fresh version of this file has to be provided by the administrator each
+# time new systems should be installed. Hence, it's not suitable for version
+# control.
+vars/network.yml