Feature load past scans inside Flint
This MR feature a dialog to load a previous scan from the Redis history.
It is good enough to be merged. It will be used as basis to provide a widget to compare scans.
- It is only supported by curve widget
- The option is available in the property widget of the curve widget
- A dialog allow to select one of the past scans
- Only scans still referenced in Redis are shown (about 24 hours)
- If the data is not anymore inside Redis, it is loaded from the HDF5 (if it was not removed, or moved)
- A loaded scan is display only in the curve widget, but like any other scans