Add functions prototype in admin_controller
administration controller optimisation
implementation of controller functions and add some utils function inside administration model
add some function prototype inside controller and model function implementation
add some form_validation and helper stuff inside controller/view
correct some treatment inside admin model and continue addUser function inside controller
continue admin development + admin model function adding and optimisation
complete admin_model and add implementation inside admin_controller
resolve conflict
Merge commit 'de933ff3cc1fb06ed3e240bc4095397ceb5c1c9c' into Sprint4

Conflicts:
	application/views/admin_addUser_view.php