Revert "Add new authors found in AR5"

This reverts commit 12f853349af97f71c6df1b3cf5453681113d08bc.
Add new authors for AR5, only with whitelisted roles

The three following roles are ignored:
* Volunteer Chapter Scientist
* Prepared under the leadership of the Working Group II Bureau
* Chapter Science Assistant

Related issue: #58
https://github.com/medea-project/ipcc-database/issues/58