CMS: various issues

[noerw]

• no login form
  • every change to another page the alert "wrong username or password appears although no password or username has to be entered (Credentials are hardcoded in frontend config #68)
• Adding location or Video the map is not displayed
• Overlays added via CMS are not shown in remote control (?)
• CMS: adding .obj overlay not working | obj overlay does not appear in video (+ while adding an obj overlay to a scenario it is not colored and difficult to position)

see also #69