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/tasks/bootstrap-debian.yml

@@ -1,17 +1,16 @@
 ---
+# Some Debian based distros ship without Python installed
+
 - name: Check if bootstrap is needed
-  raw: which "{{ item }}"
+  raw: which python
   register: need_bootstrap
   failed_when: false
   changed_when: false
   # This command should always run, even in check mode
   check_mode: false
-  with_items:
-    - python
-    - pip
-    - dbus-daemon
   environment: {}
-  tags: facts
+  tags:
+    - facts
 
 - name: Check http::proxy in /etc/apt/apt.conf
   raw: grep -qsi 'Acquire::http::proxy' /etc/apt/apt.conf
@@ -51,15 +50,18 @@
     - https_proxy is defined
     - need_https_proxy.rc != 0
 
-- name: Install python, pip, and dbus
+- name: Install python
   raw:
     apt-get update && \
-    DEBIAN_FRONTEND=noninteractive apt-get install -y python-minimal python-pip dbus
+    DEBIAN_FRONTEND=noninteractive apt-get install -y python-minimal
   become: true
   environment: {}
   when:
-    need_bootstrap.results | map(attribute='rc') | sort | last | bool
+    - need_bootstrap.rc != 0
 
-- set_fact:
-    ansible_python_interpreter: "/usr/bin/python"
-  tags: facts
+# Workaround for https://github.com/ansible/ansible/issues/25543
+- name: Install dbus for the hostname module
+  package:
+    name: dbus
+    state: present
+  become: true