CMS: creation of `cms-open-data-instructions.xml`

* (addresses #441) (PR #489)
data: FFT files for CMS Open Data Instructions

* Adds FFT files for CMS Open Data Instructions.
  (closes #441) (see PR #489)

* Amends installation instructions accordingly.

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>