Moved postgres install component to the install folder
Upgraded the irUser components to core components as the user is a core component of the cms.
Implemented hasPermission function in the user component
Permission

- Added functions to get the id of a group or a role.
- Added first drafts for functions to create, remove and check their existance for groups and roles
Fixed a typo in the path of the permission object
userController

- Added a function to get the Id of an user by it's name.
- Added a function to check if a user exists.
- Added a function to grant a permission.
- Added a function to revoke a permission.