[tools] refactor: reorganize, commonalities, moar tags, posix compat

all scripts are fully posix compliant

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

tools/cpm/fetch.sh

@@ -0,0 +1,39 @@
+#!/bin/sh -e
+
+# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# SPDX-FileCopyrightText: 2025 crueter
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+[ -z "$CPM_SOURCE_CACHE" ] && CPM_SOURCE_CACHE=$PWD/.cache/cpm
+
+mkdir -p "$CPM_SOURCE_CACHE"
+
+# shellcheck disable=SC1091
+. tools/cpm/common.sh
+
+# shellcheck disable=SC1091
+. tools/cpm/download.sh
+
+# shellcheck disable=SC2034
+ROOTDIR="$PWD"
+
+TMP=$(mktemp -d)
+
+# shellcheck disable=SC2034
+for package in "$@"
+do
+	export package
+	# shellcheck disable=SC1091
+	. tools/cpm/package.sh
+
+    if [ "$CI" = "true" ]; then
+        ci_package
+	else
+		echo "-- Downloading regular package $package, with key $KEY, from $DOWNLOAD"
+	    download_package
+    fi
+done
+
+rm -rf "$TMP"