Add playbook to run markdown linter

Set temporary to non-voting, until final documentation review.

Change-Id: Ie1a0139625c62f52277c31c307049ff417675242

.zuul.yaml

@@ -6,11 +6,21 @@
     run: playbooks/build.yaml
     nodeset: rdo-centos-9-stream
 
+- job:
+    name: rdo-mkdocs-website-pymarkdown
+    parent: base
+    description: Run markdown linter
+    run: playbooks/lint_pymarkdown.yaml
+    nodeset: rdo-centos-9-stream
+    voting: false
+
 - project:
     check:
       jobs:
         - rdo-mkdocs-website-build
+        - rdo-mkdocs-website-pymarkdown
     gate:
       jobs:
         - rdo-mkdocs-website-build
+        - rdo-mkdocs-website-pymarkdown
 

playbooks/lint_pymarkdown.yaml

@@ -0,0 +1,22 @@
+- hosts: all
+  tasks:
+    - name: Install required packages
+      become: true
+      package:
+        name:
+          - python3
+          - python3-pip
+        state: present
+
+    # https://github.com/jackdewinter/pymarkdown
+    - name: Install pymarkdown
+      pip:
+        name: pymarkdownlnt
+
+    # Ignored rules:
+    # MD013 Line length
+    # MD033 Inline HTML
+    - name: Run markdown linter 
+      command: pymarkdown -d MD013 -d MD033 scan -r .
+      args:
+        chdir: "{{ ansible_user_dir }}/{{ zuul.project.src_dir }}"