data: creation of `data-policies.xml`

* (addresses #515) (PR #525)
data: FFT files for `data-policies.xml`

* Adds FFT files for data policies.  (addresses #515) (see PR #525)

* Refactors populate script a bit.

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
fixtures: new collection "Data Policies"

* Adds new collection "Author Lists".  (closes #515) (see PR #525)

* Amends installation instructions accordingly.

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
data: better indentation of `data-policies.xml`

* Amends indentation of `data-policies.xml`.  (see PR #525)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
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>
CMS: update of `cms-learning-resources.xml`

* Leaves Hamburg tutorial in CMS Open Data Instructions collection.
  (closes #597) (PR #603)