cargo-gpu merge: move cargo-gpu crates into root crates directory

Author: Firestar99

.cargo/config.toml

@@ -1,4 +1,6 @@
 [alias]
+xtask = "run --package xtask --"
+build-test-shader = "xtask test-build"
 compiletest = "run --release -p compiletests --"
 difftest = "run --release -p difftests --"
 run-wasm = ["run", "--release", "-p", "run-wasm", "--"]