Reflectometry import - read/write project, show import warnings/errors, item selection, UI improvements
This MR is polishing the import for reflectometry to be ready for release. It contains
- Improve file import regarding content guessing and performance
- Reading & writing of project data related to file import
- Presenting import warnings/errors
- Item presentation/selection on the UI (divided in 1D/2D, include warning states)
On its way there has been a bunch of refactorings as well (renaming, getters/setters, OOD)