Bug-fix: Ground-motion interpolation failure due GMF irregularity

In case of irregular ground-motion field (not given as a grid), the bounding box created around the GMF can be bigger than the actual GMF extent and there can be cases that an entity is located in the corners, inside the bounding box where actually a ground-motion interpolation is not possible (extrapolation may be possible which is not implemened). Thus to solve this problem, instead of creating a square bounding box suing the min and max of lon and lat in the input GMF, a hull must be created and only the entities that fall within this hull can be considered. https://git.gfz-potsdam.de/dynamicexposure/globaldynamicexposure/loss-calculator/-/merge_requests/123