Add autosquash option in rebase popup

[baxyz]

Describe the feature that you'd like Click on Rebase current branch on this Commit... opens a popup with optional options (including interactive mode). However, it's not possible to specify --autosquash option.

It will be very helpfull to provide the auto-squash option in the rebase popup option.

Additional context (optional) If I do understand well, the auto-squash option is only available if the interactive mode is set. So, maybe we could also do that:

• this option could be a sub-option of interactive option entry
• this option could be selected by default if interactive option entry is enabled