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/java-maven/values.yaml

@@ -0,0 +1,27 @@
+plan:
+    package: ./java/maven/tests
+name: java-maven
+inputs:
+    TestData:
+        dir:
+            path: ./java/maven/tests/testdata
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1gxwmtwahzwdmrskhf90ppwlnze30lgpm056kuesrxzeuyclrwvpsupwtpk
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSB3VURHb25rcVdWRmMyWmVk
+            c0t4MEZscDdMWEdqMWNPRm0zRG91cnh4cnlvCllCYy9nS2F0ejZFQXBLZzgxU29n
+            V0tEcEJkQUFzdHczV3MrQjFpUHMzT1kKLS0tIFJvY2QvUjJlRE9hTTJWa1NkK2l4
+            UjFhYnZNdUxBNEtzWkVvMUoweUFnREEKbs/IGlNmDk8e3ibJSoIcE95txghXwsso
+            DL281EMf0V+ARsJY2CiehZsZB+xX7y+YfyQyoWx0xMN7bCgPu2snGg==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2021-07-08T09:55:36Z"
+    mac: ENC[AES256_GCM,data:DWdIXf9KOilX0FXRINLpHwGXAagJ9KJ1o5zrV6HKDEI8jTrNBA6HxOjlIlgC8BXAoXMNaVGl46SPh66G85eH1SR3q43kAfbCp6dpHc2bSLhX7AwqSJYFZKPPM184v1t0AWUDo+veqHcAp5m7fLS1wOVTCTOocCXjHnGuWOPr6aQ=,iv:kw31H6DCYnJJvQ6KjPtAOBeT2+BKlYJNJ0EPP2XI4wQ=,tag:47d/IHd5i0u8+BhoMP7FOg==,type:str]
+    pgp: []
+    encrypted_suffix: secret
+    version: 3.7.1