Add full support for Mac-specific keyboard layouts (#736)

* IPP for Mac, flawed initial experiments

* Cleanup and progress, but not compiling yet

* Fix error and rename nonmac -> standard

* Extentd ipp macros to accomodate mac input

* Add Mac versions of shortcuts; refactor and document the input mapper macros

* Change frontend styling for user input labels in floating menus

* Additional macro documentation

* A little more documentation

* Improve entry macro syntax

* Move input mapper macros to a separate file

* Adapt the keyboard shortcuts to the user's OS

* Display keyboard shortcuts in the menu bar based on OS

* Change Input Mapper macro syntax from {} to ()

* Fix esc key bug in Vue

* Tweaks

* Interim solution for Mac-specific hints

* Feed tooltip input hotkeys from their actions

* Fix hotkeys for tools because of missing actions

* Make Vue respect Ctrl/Cmd differences per platform

* Remove commented lines

* Code review pass by me

* Code review suggestions with TrueDoctor

* Turn FutureKeyMapping struct into ActionKeys enum which is a bit cleaner

* Add serde derive attributes for message discriminants

* Re-add serde deserialize

* Fix not mutating ActionKeys conversion; remove custom serializer

* Add serde to dev dependencies

Co-authored-by: Dennis <dennis@kobert.dev>

frontend/src/utility-functions/keyboard-entry.ts

@@ -1,5 +1,14 @@
 export function makeKeyboardModifiersBitfield(e: WheelEvent | PointerEvent | KeyboardEvent): number {
-	return Number(e.ctrlKey) | (Number(e.shiftKey) << 1) | (Number(e.altKey) << 2);
+	return (
+		// Shift (all platforms)
+		(Number(e.shiftKey) << 0) |
+		// Alt (all platforms, also called Option on Mac)
+		(Number(e.altKey) << 1) |
+		// Control (all platforms)
+		(Number(e.ctrlKey) << 2) |
+		// Meta (Windows/Linux) or Command (Mac)
+		(Number(e.metaKey) << 3)
+	);
 }
 
 // Necessary because innerText puts an extra newline character at the end when the text is more than one line.
@@ -13,7 +22,7 @@ export function getLatinKey(e: KeyboardEvent): string | null {
 	const key = e.key.toLowerCase();
 	const isPrintable = !ALL_PRINTABLE_KEYS.has(e.key);
 
-	// Control (non-printable) characters are handled normally
+	// Control characters (those which are non-printable) are handled normally
 	if (!isPrintable) return key;
 
 	// These non-Latin characters should fall back to the Latin equivalent at the key location