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-build/values.yaml

@@ -0,0 +1,30 @@
+plan:
+    package: ./docker/tests/build
+name: docker-build
+inputs:
+    TestSourceBuild:
+        dir:
+            path: ./docker/tests/build/testdata/build
+    TestSourceImageFromDockerfile:
+        dir:
+            path: ./docker/tests/build/testdata/dockerfile
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1gxwmtwahzwdmrskhf90ppwlnze30lgpm056kuesrxzeuyclrwvpsupwtpk
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSA0TXlFYWNvUldMdlRtWkEz
+            SlBEYUY1Q0thbFdSZGpaT00xQ2Jkc1J2WkdJClBXUGVTamdmZU1KNUdjam9HN0Zl
+            RjRQbVRHVjR6S3RCWlJLaElaM2ZWVG8KLS0tIDJJejFkQkxYeDdHcWdPS0p0QmJ0
+            Mm5vT1dHbFViK2ZIakNnVkZTd2lhUHMK63jJsJVLJMbQE2NkAB8qv8JnPHpvcNes
+            z17EJgl0lCLqeNHtfrTfSiIP4wq8gNLK4avCKK+WGDOIMsXPzK6RNw==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2021-07-08T09:52:50Z"
+    mac: ENC[AES256_GCM,data:IwGlcycPdVfgjRJpaAjo2dcof4N+7/RwiAwrFPp28+KK2+TwsOlecvYvbeNvDkPODhRsxzLPDf9LnLsz/w05JmpuLKSo4IxxIbaM5J7kg8GeO/naQBO9NIiLo2WqYG8KFLix3dafy9ZYQu/+WTz9gU1savZTQD81zkepWfieTTg=,iv:SOaFO4hQjNrybAtw6fSIuh62TaU0qSUQRmUITcVcGTI=,tag:CwFdENpGB/fccXTA7v5tbQ==,type:str]
+    pgp: []
+    encrypted_suffix: secret
+    version: 3.7.1