modified groupMembers and enrolment in the api

For groupMembers, I have changed the reaction to adding a group
member that is not in the course to skipping the user from terminating
the request. I have also added the task of removing members that
are not in the new list.

for enrolment, I have changed the reaction to enroling users that
do not exist to skipping the user from terminating the request.
Similar to groupMembers, users already enroled in the course but do
not appear in the new list would be removed.

I have added tests for the api to test the changes mentioned above.
added more tests for moving a group of students from a course

Some of the tests I have added includes the changes I have made
to the features, which includes allowing students on the list
to not be in the source course, allowing moving students from
courses that does not have a survey event, and the new message
which notes whether a student has submitted to a peer evaluation
or not.

I have also added a new column to the events index which is the
number of groups in the event. If the event is a survey, it will
say N/A since surveys do not have groups. If the event has no groups
a red "0" will be given to warn the instructor that no groups are
added.
committed csv files missed from the last commit