Print non-breaking space to prevent `<dd>` collapse

If the `cmd` is empty, its `<dd>` collapses because it floats with no
contents. Print a non-breaking space in its place to make sure it
does not collapse.

Fixes #366.
Render “Staged” in task list with yellow health badge

This was the intended visual effect for the task list, but it was lost
in an earlier refactoring

* Extract the logic of a health badge into a BadgeComponent. If `type`
  is provided, the badge gets a gray badge and a health indicator.
fixes #397 Docker image field is lost if  field is not set
Updated version number