Godot script editor does not respect Mac keyboard bindings

[sean256]

Godot version: 312

OS/device including version: macOS 10.14.6

Issue description:
Mac allows users to override key bindings for customization. One such popular customization is to remap the home and end keys to behave like every other OS. For example

~/Library/KeyBindings/DefaultKeyBinding.dict

{
/* Remap Home / End */
"\UF729"  = "moveToBeginningOfLine:";                   /* Home         */
"\UF72B"  = "moveToEndOfLine:";                         /* End          */
"$\UF729" = "moveToBeginningOfLineAndModifySelection:"; /* Shift + Home */
"$\UF72B" = "moveToEndOfLineAndModifySelection:";       /* Shift + End  */
}

Steps to reproduce:
Use this custom Mac keybinding file (note you have to log out and back in) and try to use the home and end key in Godot. Godot will treat home and end as if it were the Mac default.

Minimal reproduction project:
N/A

[bruvzg]

Currently, text editor key bindings are hardcoded here - https://github.com/godotengine/godot/blob/master/scene/gui/text_edit.cpp#L3385