Proposals/Done/Groups csv create

The following changes would need to be made to allow this.

Create a groupid or shortname which is unique (but can also be null)
Create a csvfile structure for uploading csvs to create groups
Create a csvfile structure for uploading csvs to enrol users into groups

Group ID

The group id will be a unique nullable field that holds a shortname or groupid which is different from the already present id field (which is only for the database)

CSV to create groups

This file will need to have group name, group shortname, group desc, group type

CSV to enrol users into groups

This file will need to have group shortname, user studentid

- The studentid will be focused on to start with, then other ways of identifying the user may be created, such as username or email