[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/cpm/package/util/replace.sh

@@ -0,0 +1,13 @@
+#!/bin/sh -e
+
+# SPDX-FileCopyrightText: Copyright 2025 crueter
+# SPDX-License-Identifier: LGPL-3.0-or-later
+
+# Replace a specified package with a modified json.
+
+FILE=$(echo "$CPMFILES" | xargs grep -l "\"$1\"")
+
+jq --indent 4 --argjson repl "$2" ".\"$1\" *= \$repl" "$FILE" >"$FILE".new
+mv "$FILE".new "$FILE"
+
+echo "-- * -- Updated $FILE"