OO-3473	: delete the temporary files only at the end of the wizard and not after the first created element

OO-3472: rewrite the delete routine to delete only the file of the edited checkbox, implement a check to not delete the file if it's used by an other checkbox

OO-3469: better check variable in velocity template, check if the candidate session exists in disposing phase

OO-3296: don't upgrade manager roles if administrator and decouple every role, remove double update roles method...

OO-3296: implement migration tool from institution resource manager to learn resource manager based on organizations

OO-3303: Survey course node with configurations for executor and report viewer roles, surveys are always anonymous

OO-3457: only use the latest candidate session in the correction workflow and don't use a cached one

OO-2789: Integration of JavaScript library iFrameResizer to automatically set the size of iFrames as a function of its content

OO-3297, OO-3301: refactor security group management operations in its own DAO, implement isInOrganisation mfunction for course expert rules

OO-3297: refactor the user management to use organization for managing the roles instead of named security groups