Dev/multiple rois in aare (#263)

Reading multiple ROI's for aare 

- read_frame, read_n etc throws for multiple ROIs
- new functions read_ROIs, read_n_ROIs 
-  read_roi_into (used for python bindings - to not copy) 

all these functions use get_frame or get_frame_into where one passes the
roi_index
## Refactoring:
- each roi keeps track of its subfiles that one has to open e.g.
subfiles can be opened several times
- refactored class DetectorGeometry - keep track of the updated module
geometries in new class ROIGeometry.
- ModuleGeometry updates based on ROI

## ROIGeometry: 
- stores number of modules overlapping with ROI and its indices
- size of ROI 

Note: only tested size of the resulting frames not the actual values

---------

Co-authored-by: Erik Fröjdh <erik.frojdh@psi.ch>
Co-authored-by: Erik Fröjdh <erik.frojdh@gmail.com>

python/src/np_helper.hpp

@@ -84,4 +84,21 @@ struct fmt_format_trait<Cluster<T, ClusterSizeX, ClusterSizeY, CoordType>> {
 };
 
 template <typename ClusterType>
-auto fmt_format = fmt_format_trait<ClusterType>::value();
+auto fmt_format = fmt_format_trait<ClusterType>::value();
+
+/**  
+* Helper function to allocate image data given item size and shape 
+* used when we want to fill a numpy array and return to python
+*/
+py::array allocate_image_data(size_t item_size,
+                              const std::vector<size_t> &shape) {
+    py::array image_data;
+    if (item_size == 1) {
+        image_data = py::array_t<uint8_t>(shape);
+    } else if (item_size == 2) {
+        image_data  = py::array_t<uint16_t>(shape);
+    } else if (item_size == 4) {
+        image_data = py::array_t<uint32_t>(shape);
+    }
+    return image_data;
+}