[tools, cmake] refactor: update/hash check scripts, use tags for some more deps, proper CPMUtil separation (#2666)

Uses tags for a bunch of deps that can use them

Also adds a bunmch of scripts to tools/cpm, notably for checking hashes
and checking for updates.

TODO for the future:
- CI target to check hashes
- Weekly CI to check for updates

Need to get that other CI runner up

additional stuff

- Ports gentoo fixes
- makes solaris work (TODO: sdl2)
- way better docs
- properly separates CPMUtil as a standalone project

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2666
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

tools/shellcheck.sh

@@ -0,0 +1,11 @@
+#!/bin/sh -e
+
+# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# fd is slightly faster on NVMe (the syntax sux though)
+if command -v fd > /dev/null; then
+	fd . tools -esh -x shellcheck
+else
+	find tools -name "*.sh" -exec shellcheck -s sh {} \;
+fi