Overworld Backend: Teleporter Implementation & Integration

[WuestFlorian]

Description

Currently, the teleporter data is not saved in the overworld backend. Secondly, there are no teleports set up in any world. That needs to be changed.

DoD

• [x] there exist teleporters at least in world 1 and 2
• [x] the teleporter data is saved in the backend
• [x] add description of teleporter system in the manual
• [x] add test plans