Feature picking shader compatibility
Picking shaders are now loaded using shader generator to work for opengl 3.0 and opengl 3.1 profiles if required extensions are available.
ci build job is https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/OpenFlipper-Free/pipelines/6892
please remove respective branch after merging https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/OpenFlipper-Free/commits/CIJobforFeaturePickingShaderCompatibility
please also merge https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Type-PolyLine/merge_requests/1 and https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Type-Camera/merge_requests/2 when merging this MR
Edited by Martin Schultz