Fix markdown tables on docs.podman.io

Sphinx with recommonmark cannot render markdown tables at all.
There is a python package called `sphinx-markdown-tables` which
adds the markdown table support to recommonmark.
https://pypi.org/project/sphinx-markdown-tables/

By utilising this package we don't have to change our doc format.

Signed-off-by: Paul Holzinger <paul.holzinger@web.de>

docs/source/conf.py

@@ -28,9 +28,14 @@ author = "team"
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = [
-    "recommonmark",
+    'sphinx_markdown_tables',
 ]
 
+source_parsers = {
+    '.md': 'recommonmark.parser.CommonMarkParser',
+}
+
+
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ["_templates"]