Add process stream in _tomwer_processes.h5
For now wwe are saving processes one after the others and overwritting them. But there is some bottleneck. For example if we process a first time a dataset. Them a second time with differente processes this can be a mess. We would have to look at processing to know what is part of the workflow stream or not.
We should add a "process stream" or something like that to know what has been processed and when maybe. Or clean the processes at one point in the canvas. This part need to be clean.
The identifier now used on the processview might be more pointing to an entry / group of an NXprocess pointing to the dataset + TomoScanBase object as a dictionary.