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-push/values.yaml

@@ -0,0 +1,28 @@
+plan:
+    package: ./docker/tests/push
+name: docker-push
+inputs:
+    TestRegistry.secret:
+        secret: ENC[AES256_GCM,data:ooc+0IjYtX9tkM7q1i4Ws6CorZsWtGQzHbjGx+j892iTZC7Q,iv:asdJzuRAHBRhD/FlkEd1VvX1tIz/qupBL7sMQWxZL5E=,tag:yuTyDx7hZeC+cmHx6tspmQ==,type:str]
+    TestRegistry.username:
+        text: daggertest
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1gxwmtwahzwdmrskhf90ppwlnze30lgpm056kuesrxzeuyclrwvpsupwtpk
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBrcnpRZ203QzhtKzc3bzF4
+            Y002V0JUUnNZMks2VS83SjBOdVZid1dxbTJjCmc5VGtvM3lOejEvQ3VMZ1ZyZElZ
+            Skd3ZWxRMHdQRHdtZFBYUFMweDFlL28KLS0tIHhHeUh4a2gvb2w3UTEyNFZaK0dS
+            UjFJYTc1UUUzSFVkZjQ2blRsSGpVdVEKOanMR3+WlAgoDfqTUW7WPW1ytT3NdkTX
+            4Rqo49QmnuKFJ9tKoBFQOqgIo8E/lpcOkeIUiy5e/35FvsZ/KFk/pg==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2021-07-08T09:53:44Z"
+    mac: ENC[AES256_GCM,data:WGLgBuMtbCVeUGmj8ImZw5IG4H7d33rAcZdaN42jTI+O6Mb9F1qpaF4jFT52KFFTeImMjWP7QKDWhyn6aAWnZfHukMooV7QCxo91PTAQPuA26T/H32bDy04rorax2bUAdw4dJa/5Gl2H2A/TP/cWSwimD5O56k70NKZ+2A7/DxM=,iv:g/BcUDplaxiglPAF9s+5/Z5Eq97OyizpN4ulkqPtJ44=,tag:+5YH6P84dw3ApQd4vQEEWw==,type:str]
+    pgp: []
+    encrypted_suffix: secret
+    version: 3.7.1