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/.dagger/env/docker-pull/values.yaml

@@ -0,0 +1,26 @@
+plan:
+    package: ./docker/tests/pull
+name: docker-pull
+inputs:
+    ref:
+        text: docker.io/daggerio/ci-test:tyrgcrtlasex@sha256:3b308dec2f3d4c563b9c71ce4ddc660e476b899d06fa37f3b9fef350c1062a1f
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1gxwmtwahzwdmrskhf90ppwlnze30lgpm056kuesrxzeuyclrwvpsupwtpk
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSA0WFI2ZGFUOWgvNkdlZ3Na
+            dEE5dTlVQi8vUVJqcHUxWE9GSmdnNmZLMHhRCm1sbFlJbEw1ZVFSVXU4MCtkT09l
+            dVR1WE5XUkVpSXA3aXN5TzZLaWJRNnMKLS0tIDZINGpzODdXVUdKVVpFMjFUbUFO
+            SG1raUVNTzZIWDltV1pOS3hySHlJeWcKg3blmstOGcxtPww513+mAEA0MWOXwNAT
+            5ngRvG6MraW3g9dhIuUYOwjuJyz1Z07/DBEocSxnjSyw45ZCkM1/9Q==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2021-11-23T18:15:32Z"
+    mac: ENC[AES256_GCM,data:+HpG1ZDND1Japu1hLgTVKF6CfEUbYp+sEBpv0WtsCHcHGYeYVkZT8ZJKajWlz8uFfikpKv76FkBw8XqKVXyPZYTQWuo9VvmPTF5HajiVE6kP5Ax3/5Sh7ecwfGdbqE3mQoj+jaQE8NBnGbCBljij/xFYW63fIaurqsyPWTQl2YI=,iv:fBPseUNueHO4ZUnlwDljfAwUvi4UyjGysXMTCmoAgYw=,tag:Pg4dGX4/05SahATlE6zrsA==,type:str]
+    pgp: []
+    encrypted_suffix: secret
+    version: 3.7.1