installer: make it run on red hat

[tpurschke]

Installation documented here: https://github.com/CactuseSecurity/firewall-orchestrator/blob/master/documentation/developer-docs/ansible-redhat.md

• download from https://developers.redhat.com/products/rhel/download

• install minimal server - do not select "connect to red hat insight"

• do test install

• fix all issues during installation

• see also https://www.heise.de/news/Kostenloses-RHEL-statt-CentOS-5030972.html

• main issue is to know the package names per distribution

• other issues include name and location of Linux Distribution dependent config files

• package updates/upgrades (apt update, apt upgrade) will have to be handled with when statements per OS

• replace all apt module occurences with package module:
  bad:

     - name: Install packages for docker download n installation
       apt:
         name: "{{ packages }}"
       vars:
         packages:
         - gnupg2

good:

   - name: Install packages for python pip3 n virtualenv
     package:
        name: "{{ packages }}"
     vars:
        packages:
          - python3-pip
          - python3-virtualenv

• need to add further case distinctions like

          when: ansible_facts['distribution'] == "Ubuntu"
          when: ansible_facts['distribution'] == "Debian"

[alf-cactus]

Cut out centos here and created new issue #712 for it