Add the option for revision already segmented cases

[maxradx]

Is your feature request related to a problem? Please describe.
If the User wants to revise some already made annotations, the option to enter a revision mode should be added.

Describe the solution you'd like
Option to select revision mode from the configuration pop-up window at Slicer startup.

Describe alternatives you've considered
implementing anoter module.

Additional context
Add any other context or screenshots about the feature request here.