Define and implement specs for bootstrap-os (#4455)

* Add README to bootstrap-os role

* Rework bootstrap-os once more

* Document workarounds for bugs/deficiencies in Ansible modules
* Unify and document role variables
* Remove installation of additional packages and repositories
* Merge Ubuntu and Debian tasks
* Remove pipelining setting from default playbooks
* Fix OpenSUSE not running its required tasks

roles/bootstrap-os/defaults/main.yml

@@ -1,16 +1,14 @@
 ---
-pip_python_coreos_modules:
-  - httplib2
-  - six
-
-override_system_hostname: true
-coreos_auto_upgrade: true
-
+## CentOS/RHEL specific variables
 # Install epel repo on Centos/RHEL
-epel_enabled: false
+centos_epel_enabled: false
+# Use the fastestmirror yum plugin
+centos_fastestmirror_enabled: false
 
-# CentOS/RedHat Extras repo
-extras_rh_repo_base_url: "http://mirror.centos.org/centos/$releasever/extras/$basearch/"
-extras_rh_repo_gpgkey: "http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-7"
-# Caching extras packages after installation
-extras_rh_rpm_keepcache: 0
+## CoreOS specific variables
+# Disable locksmithd or leave it in its current state
+coreos_locksmithd_disable: false
+
+## General
+# Set the hostname to inventory_hostname
+override_system_hostname: true