"yamlfile" module file spec

The "yamlfile" module included with libcrange allows you to specify clusters using a directory full of yaml files.

By default, it looks in /etc/range/*.yaml for these files. Each cluster is represented by one file named CLUSTER.yaml, where CLUSTER is the name of the cluster you want.

Example:

$ cat /etc/range/test.yaml
CLUSTER: host1..100.test.com
APPS: 
  - frontend
  - backend
  - mysql