Introduce simplified Default credential provision

As the first step in credential consolidation, we replace
injection of application default credential in for KMS and
Drive.

Tests:
- for Drive, tested with exportDomainLists and exportReservedTerms.
- For KMS, used CLI commands (get_keyring_secret and update_kms_keyring) to change and
  restore secret for one key.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=211819859

java/google/registry/export/BUILD

@@ -16,7 +16,6 @@ java_library(
         "//java/google/registry/mapreduce/inputs",
         "//java/google/registry/model",
         "//java/google/registry/request",
-        "//java/google/registry/request:modules",
         "//java/google/registry/request/auth",
         "//java/google/registry/storage/drive",
         "//java/google/registry/util",