Added the ability to specify platform-specific editorPath

[ogapo]

• support config of the form godotTools.editorPath.(windows|macos|linux)-(x86_64|arm64).godot(3|4)
• match godot's buildsystem terms for familiarity
• move all path manipulation hacks into clean_godot_path
• tried to make sure all code that needs the editor path consistently use the util functions

BUGFIX: expand ${env:X} into the string. Previous code replaced the whole string if it contained an env tag and only matched the first one.

Per some discussion on #502 I realized this is the only thing stopping folks from using workspace config (committed to source control) for configuring prebuilt binaries in their projects given the paths are already treated as workspace relative (if they're not absolute).

[DaelonSuzuka]

FYI I'm out of town until next week but I'll review this when I get back.

[ogapo]

@DaelonSuzuka wondering if you have any cycles to have a look at this? Thanks!