[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 <[email protected]>
Reviewed-by: MaranBr <[email protected]>

tools/cpm/url-hash.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+# SPDX-FileCopyrightText: 2025 crueter
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+SUM=$(wget -q "$1" -O - | sha512sum)
+echo "$SUM" | cut -d " " -f1