Improve backup/restore #6958
Description
The current state of the backup/restore code was satisfactory for the Beta release but there is still a series of tools to be supported that are currently unsupported in the Moodle export format (we are now using Moodle's .mbz format for Chamilo course backups, by default).
Also, we are not sure if we import correctly all the contents from Chamilo 1.11.x yet, but documents are correctly imported. So are tests, but hotpotatoes and hotspots need more testing.
Attention has to be put in the conversion of items (from 1.11) to resources (in 2.0) in general.
See #6870 for previous work.