Add progress bar to load and save files

[paulojamorim]

Add progress bar for the following functionalities:

• Open project file
• Save project file
• Save project as (all formats)
• Export project (all formats)
• Import other files
• Export 3D surface
• Import surface file (all formats)

The wx.ProgressDialog component should be used: https://docs.wxpython.org/wx.ProgressDialog.html

[Abo-Omar-74]

Is there a metadata about operations of Saving/Loading and other functions stated above? To use it with "update" function of wx.ProgressDialog to display the operation that is currently executed.

Or you are expecting the contributor to understand these operations and set this metadata manually .

Or are you okay not to include this metadata?