Draft: GUI: simplify loading datafields

Mikhail Svechnikovrequested to merge
i418 into main

Currently we have numerous services responsible for saving and loading datafield files: DatafieldIOService, DatafieldIOHistory, DatafieldDirHistory, DatafieldSaveInfo, SaveService, SaveThread.

This is quite complicated to read and understand. The idea is to read and write the datafields together with reading and writing the xml data. So the DataItem::saveDatafield() should be called from DataItem::writeTo() and DataItem::loadDatafield() should be called from DataItem::readFrom().

Temporary until the SessionModel refactoring is finished, saveDatafield() and loadDatafield() will be called from JobItem and RealItem.

This MR does the change only for loading datafiles, it is the first step to do #418 (closed), #364 (closed), #365 (closed). The second step will be about saving datafiles.

Edited by Mikhail Svechnikov

Merge request reports