Create security [Medium priority]

[jefmoura]

• [x] Create a new file /security/security.xml to hold the groups
• [x] Edit the file /security/ir.model.access.csv with the access rights to the models
• [x] Update openerp**.py** to add the new data files to it
• [x] Create groups
  • Employee
  • Company Manager
  • Agent
  • HelpDesk Manager