Store percentage and version

Add percentage and version columns to trainees
table.

Percentage refers to the training task completion
percentage.

Version refers to the version of the Training Activity
from which the report was received.

Signed-off-by: Martin Abente Lahaye <tch@sugarlabs.org>
Release 0.2.0-1

Signed-off-by: Martin Abente Lahaye <tch@sugarlabs.org>