cue modules: move stdlib to pkg/alpha.dagger.io

In preparation for Europa, we will vendor multiple CUE modules:

- `pkg/alpha.dagger.io`: legacy non-europa packages
- `pkg/dagger.io`: core Europa packages
- `pkg/universe.dagger.io`: Europa universe

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

pkg/alpha.dagger.io/package.json

@@ -0,0 +1,11 @@
+{
+  "license": "Apache-2.0",
+  "scripts": {
+    "test": "bats --report-formatter junit --jobs 4 ."
+  },
+  "devDependencies": {
+    "bats": "https://github.com/bats-core/bats-core#master",
+    "bats-assert": "https://github.com/bats-core/bats-assert",
+    "bats-support": "https://github.com/bats-core/bats-support"
+  }
+}