Improve README

* expand YRP in the headline (deprecating the current first paragraph)

* Rename section ``What does it do`` to ``What exactly does it do`` as
  it includes details that depend on the ``workflow`` section

* Add first pargraph with as brief description as possible

* Split ``workflow`` section into configuration part and actuall
  workflow part

* Use ``inline literall`` syntax instead of the incorrectly used
 `interpreted text`