add function to create XRSite from simulation_result.flow_box() allowing precalculated sites including effects of neighbouring farms

Implemented wake_radius() function for the different wake models and modified args4turb to be independant from deficit

- add test, which tests aep probability normalizing for two turbines
- remove not-needed autograd switch

Added different superposition models for turbulence intensity, as StenFrandsen uses effective turbulence intensity instead of the usual added turbulence intensity

Move the split line between wake and blockage is set slightly downstream to handle numerical inaccuracy in the trigonometric functions that calculates dw_ijlk

add selfsimilarity blokage model
prepare for gradients
New structure. Old WakeModel mainly in new EngineeringWindFarmModel
add deflectionmodel
update documentation