refactor: move iam-policy code to java-iam-policy folder (#12834)

This folder contains the google-cloud-iam-policy client

Towards #12735
Towards googleapis/librarian#5326

There is also an existing sdk-platform-java/java-iam folder which will
need to move to the top level to be generated

---------

Co-authored-by: cloud-java-bot <cloud-java-bot@google.com>

Author: chingor13

generation_config.yaml

@@ -1299,12 +1299,13 @@ libraries:
   - proto_path: google/cloud/hypercomputecluster/v1beta
   - proto_path: google/cloud/hypercomputecluster/v1
   requires_billing: true
-- api_shortname: iam
+- api_shortname: iam-policy
   name_pretty: IAM
   product_documentation: n/a
   api_description: n/a
   release_level: stable
   distribution_name: com.google.cloud:google-iam-policy
+  api_id: iam.googleapis.com
   client_documentation: https://cloud.google.com/java/docs/reference/proto-google-iam-v1/latest/history
   excluded_poms: proto-google-iam-v1-bom,google-iam-policy,proto-google-iam-v1
   excluded_dependencies: google-iam-policy

java-iam/.OwlBot-hermetic.yaml java-iam-policy/.OwlBot-hermetic.yamljava-iam/.OwlBot-hermetic.yaml renamed to java-iam-policy/.OwlBot-hermetic.yaml

@@ -1,5 +1,5 @@
 {
-  "api_shortname": "iam",
+  "api_shortname": "iam-policy",
   "name_pretty": "IAM",
   "product_documentation": "n/a",
   "api_description": "n/a",
@@ -8,7 +8,7 @@
   "transport": "both",
   "language": "java",
   "repo": "googleapis/google-cloud-java",
-  "repo_short": "java-iam",
+  "repo_short": "java-iam-policy",
   "distribution_name": "com.google.cloud:google-iam-policy",
   "api_id": "iam.googleapis.com",
   "library_type": "GAPIC_AUTO",