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/gcp/gcp.cue

@@ -0,0 +1,18 @@
+// Google Cloud Platform
+package gcp
+
+import (
+	"alpha.dagger.io/dagger"
+)
+
+// Base Google Cloud Config
+#Config: {
+	// GCP region
+	region: dagger.#Input & {*null | string}
+	// GCP zone
+	zone: dagger.#Input & {*null | string}
+	// GCP project
+	project: dagger.#Input & {string}
+	// GCP service key
+	serviceKey: dagger.#Input & {dagger.#Secret}
+}