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/os/values.yaml

@@ -0,0 +1,23 @@
+plan:
+    package: ./os/tests/os
+name: os
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1gxwmtwahzwdmrskhf90ppwlnze30lgpm056kuesrxzeuyclrwvpsupwtpk
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSA0bDM5blE0cC9LNHkxZmEy
+            bitYcjhMOHhrWE5pRm90Qyt4S200ZTN0Q1d3Clh2VmdKQjdGUGdKaThmaktwN1F6
+            aXZpellwbHpkb3pMb1NMNXVJYnFUMmMKLS0tIFNiZGlBNjE3UjlXWnBjZ3hwSWto
+            STlrbFNHZGFRUVQ1S1RIaGVyWktNV0kKo9AFURi/BKI+JuGYVuOrsw3eJU3s66Im
+            FCc5YCzrsjX+Y26Su+XW81fTWkcC910e/g+tlZbEFWKZYa8qu1VkqA==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2021-07-08T09:56:27Z"
+    mac: ENC[AES256_GCM,data:a69jnTQsVKzWB+52XfoCldJUev6YqJTpdVFBhgbx4WXW9x3YNwRQy4fguiNqiXo/BmiVoHQrPEQsUUHkmsB8r/pOVzq0SlsRRqLLnkJRTdoRSzP8BnOvMxk9Am2g8Y0a7smXAgmkbDzVLLBOZXyGROb1geTrGxeCFgF9AjGLJrM=,iv:5cUq11KBRxrWapdpvC1VqMQ0otyGZbHuU/C/FsIM0+o=,tag:QD4KCFnGxw6eH/fmSoByYQ==,type:str]
+    pgp: []
+    encrypted_suffix: secret
+    version: 3.7.1