CMS: masterclass file update

* Adds limitations and selection information.  (PR #427)
CMS: usage information for ig files

* Adds usage information for masterclass ig files.  (PR #427)
CMS: CSV file metadata update

* Adds limitations, selection information, validation information.
  (PR #427)
CMS: CSV file metadata update

* Adds usage field. (closes #342) (PR #427)
CMS: small fixes for CSV files

* Create another 567 field and fixes variable -> value typo.
  (PR #427)
CMS: addition of masterclass files

* Adds record for CMS masterclasses files and adds FFT files for cache
  populating script.  (closes #460) (PR #427)
CMS: fix FFT path typo for masterclasses

* Fixes FFT path typo for masterclasses.  (PR #427)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
records: `methodology_note` is now a list

* Amends data model to force `methodology_note` to always be list.
  (PR #427)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
templates: new treatment of `methodology_note`

* Amends all templates WRT `methodology_note` that is now always a
  list.  (PR #427)

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