[cmake, docs, tools] update CPMUtil (#3183)

Rewrote the entire tooling scheme. That's about it, just make sure
tooling works as expected everywhere.

Signed-off-by: crueter <crueter@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3183
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: Lizzie <lizzie@eden-emu.dev>

tools/cpmutil.sh

@@ -0,0 +1,78 @@
+#!/bin/sh -e
+
+# SPDX-FileCopyrightText: Copyright 2025 crueter
+# SPDX-License-Identifier: LGPL-3.0-or-later
+
+# shellcheck disable=SC1091
+
+ROOTDIR=$(CDPATH='' cd -- "$(dirname -- "$0")/cpm" && pwd)
+SCRIPTS="$ROOTDIR"
+
+. "$SCRIPTS"/common.sh
+
+RETURN=0
+
+die() {
+	echo "-- $*" >&2
+	exit 1
+}
+
+usage() {
+	cat <<EOF
+Usage: $0 [command]
+
+General command-line utility for CPMUtil operations.
+
+Commands:
+    package Run operations on a package or packages
+    format  Format all cpmfiles
+    update  Update CPMUtil and its tooling
+    ls      List all cpmfiles
+    migrate Convert submodules to a basic cpmfile
+
+Package commands:
+    hash    	Verify the hash of a package, and update it if needed
+    update  	Check for updates for a package
+    fetch   	Fetch a package and place it in the cache
+    add     	Add a new package
+    rm      	Remove a package
+    version 	Change the version of a package
+    which   	Find which cpmfile a package is defined in
+    download 	Get the download URL for a package
+
+EOF
+
+	exit $RETURN
+}
+
+export ROOTDIR
+
+while :; do
+	case "$1" in
+	-h | --help) usage ;;
+	ls)
+		echo "$CPMFILES" | tr ' ' '\n'
+		break
+		;;
+	format)
+		"$SCRIPTS"/format.sh
+		break
+		;;
+	update)
+		"$SCRIPTS"/update.sh
+		break
+		;;
+	migrate)
+		"$SCRIPTS"/migrate.sh
+		break
+		;;
+	package)
+		shift
+		"$SCRIPTS"/package.sh "$@"
+		break
+		;;
+	*) usage ;;
+	esac
+
+	shift
+done