Add tracking option for PV plants

[danielfeismann]

Tracking mode of PV models can increase the utilization solar radiation. To be able to simulate this as well the PV-Model should be adapted.

To do

• [ ] if single axis tracking is possible the orientation of the tracking axis needs to be given (east-west, north-south, parallel to earth-axis)
• [ ] add parameter to PV-Model in PSDM to define if PV plant has none tracking, single axis tracking (see next task) or two axis tracking
• [ ] include angles for tracking surfaces (see Duffie p.20 ff)
• [ ] add tests for tracking surfaces (see Duffie)
• [ ] extend PV-Model IT also by tracking
• [ ] extend documentation