feat: Apply Entry Dialog Changes via Enter Key

[ternison]

Problem
When creating folders or renaming files pressing the enter key does not apply the changes directly.
This can be a bit of a nuisance in cases in which you want to for example quickly add lots of folders, since the only other options to apply it are tabbing two times and then using the enter key or using your mouse.

entrydialog.mp4

Solution
Within the entry dialog widget: Capture the enter key being pressed while the entry is active and emit a clicked signal to the apply key.
This seems like a logical change to be applied to all entry dialog widgets, since the apply_button is highlighted blue.

[Doublonmousse]

This seems like a logical change to be applied to all entry dialog widgets, since the apply_button is highlighted blue.

Yes it is. There's probably more dialogs and tweaks we can apply this too (in #1486 the one I had in mind was the xournalpp import dialog)

[ternison]

Yes it is. There's probably more dialogs and tweaks we can apply this too (in #1486 the one I had in mind was the xournalpp import dialog)

Yep, agreed! There are a few tweaks on the table. Added a few more instances with unintuitive enter bindings to #1486