Role based authorization
Existing endpoints need to make sure that the user which invoked the endpoint actually has permission to do so. New methods have to be added which would check the database for the permission that a user has. Frontend of !293 (closed) and !286 (closed) has been merged to this branch. Roles table of !288 (closed) is also merged here Users are prevented access to features based on their role. Closes #464 #477 #471 #467 #465