Hosts are not configurable

[ccravens]

Feature Request or Enhancement

• Feature []
• Enhancement [X]

Summary of Request In site.yml, hosts is not configurable and is hard-coded to all

- name: Run RHEL8 CIS hardening
  hosts: all
  become: true

  roles:

      - role: "{{ playbook_dir }}"

Describe Alternatives You've Considered A clear and concise description of any alternative solutions or features you've considered.

Suggested Code Submitting PR that adds a hosts variable to defaults, defaulted to all and uses the variable in the site.yml file.