Use hier_config's sane defaults instead of requiring options/roles defined in a role

[iamroddo]

hier_config is great looking tool. I see what I think is an issue with hconfig-remediation-ansible. As I understand hier_config comes with a set of sane defaults which are embedded in hier_config/options.py, setting the 'os' for a config uses those defaults. It seems to me that the 'os' cannot simply be set in the collection, rather the 'role_os' is set which is used to determine a set of options for that OS, which must be provided in roles/{role_os}/{vars,templates}, irrespective of whether the sane defaults are acceptable. While the 'os' as an input parameter for hier_config is derived from the value of 'role_os'.

This makes it more difficult to use this collection out of the box than the Python library.

It seems to me that the 'os' should be directly settable, independently of the role_os. The default values of options and tags should be the sane defaults of hier_config with the setting of 'os_role' optional.

[iamroddo]

I have opened a PR to allow roles/{role_os}/{vars,templates} not to be defined and to use default options for that OS from hier_config