Add cursor shortcuts for editor on Mac

[MRxRadex]

Issue description:
Please add combinations for the Mac version of the editor like:
"Cmd + left arrow key" - move cursor to the start of the line.
"Cmd + right arrow key" - move cursor to the end of the line.
"Cmd + Shift + left arrow key" - move cursor to the start of the line with selection.
"Cmd + Shift + right arrow key" - move cursor to the end of the line with selection.
"Cmd + Delete" - delete line.

P.S. Add these not for scripting only, but to the entire engine in menus, etc.

[DrMoriarty]

I think that more interesting is to make ability to change all hotkeys for script editor view.
I also use mac, but I prefer to use emacs like hotkeys. I worked on this problem at https://github.com/DrMoriarty/godot/tree/emacsify but it has very dirty code so I didn't made PR.

May be anybody has any thoughts about making keys customisation?

[maho]

From my point of view, I would like to have home/end buttons to behave like in Linux. However, then go to beginning and end of the file, and that's drives me mad. I would love to be able to customize it.

[sean256]

The issue is that key bindings are hard coded, otherwise you'd be able to map them at an OS level to do just that. #34129

[Calinou]

Adding support for customizing TextEdit shortcuts in the editor will probably have to wait for #31739 to be done. (We can't add more editor-only code to TextEdit due to #29730.)

[40detectives]

For the meantime, I get by using a key remapper software that hooks up the input before handling it to godot. In my case I use bettertouchtool but maybe could make it work with karabiner or you keyboard manufacturer software if any.

[Paulb23]

Fixed by #43663