[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: #2666
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

tools/README.md

@@ -0,0 +1,21 @@
+# Tools
+
+Tools for Eden and other subprojects.
+
+## Third-Party
+
+- [CPMUtil Scripts](./cpm)
+
+## Eden
+
+- `shellcheck.sh`: Ensure POSIX compliance (and syntax sanity) for all tools in this directory and subdirectories.
+- `llvmpipe-run.sh`: Sets environment variables needed to run any command (or Eden) with llvmpipe.
+- `optimize-assets.sh`: Optimize PNG assets with OptiPng.
+- `update-cpm.sh`: Updates CPM.cmake to the latest version.
+- `update-icons.sh`: Rebuild all icons (macOS, Windows, bitmaps) based on the master SVG file (`dist/dev.eden_emu.eden.svg`)
+    * Also optimizes the master SVG
+    * Requires: `png2icns` (libicns), ImageMagick, [`svgo`](https://github.com/svg/svgo)
+- `dtrace-tool.sh`
+- `lanczos_gen.c`
+- `clang-format.sh`: Runs `clang-format` on the entire codebase.
+    * Requires: clang