Export/convert the posts from the current site

[extua]

When I have login to the site:

• Use ultimate markdown plugin to export posts in markdown files.
• Process front matter.
• Backup whatever photos in the media directory.

[extua]

For converting Markdown with YAML front matter to TOML front matter https://discourse.gohugo.io/t/howto-convert-your-front-matter-from-toml-to-yaml/332