chore: removing outdated files in favor of https://github.com/googleapis/google-cloud-java/tree/main/java-iam

[suztomo]

The code in this repository has moved to https://github.com/googleapis/google-cloud-java/tree/main/java-iam

[generated-files-bot]

Warning: This pull request is touching the following templated files:

• .github/CODEOWNERS
• .github/ISSUE_TEMPLATE/bug_report.md
• .github/ISSUE_TEMPLATE/feature_request.md
• .github/ISSUE_TEMPLATE/support_request.md
• .github/PULL_REQUEST_TEMPLATE.md
• .github/blunderbuss.yml
• .github/generated-files-bot.yml
• .github/snippet-bot.yml
• .github/sync-repo-settings.yaml
• .github/trusted-contribution.yml
• .github/workflows/approve-readme.yaml
• .github/workflows/auto-release.yaml
• .github/workflows/ci.yaml
• .kokoro/build.bat
• .kokoro/build.sh
• .kokoro/coerce_logs.sh
• .kokoro/common.cfg
• .kokoro/common.sh
• .kokoro/continuous/common.cfg
• .kokoro/continuous/java8.cfg
• .kokoro/dependencies.sh
• .kokoro/nightly/common.cfg
• .kokoro/nightly/integration.cfg
• .kokoro/nightly/java11.cfg
• .kokoro/nightly/java7.cfg
• .kokoro/nightly/java8-osx.cfg
• .kokoro/nightly/java8-win.cfg
• .kokoro/nightly/java8.cfg
• .kokoro/nightly/samples.cfg
• .kokoro/populate-secrets.sh
• .kokoro/presubmit/clirr.cfg
• .kokoro/presubmit/common.cfg
• .kokoro/presubmit/dependencies.cfg
• .kokoro/presubmit/graalvm-native.cfg
• .kokoro/presubmit/integration.cfg
• .kokoro/presubmit/java11.cfg
• .kokoro/presubmit/java7.cfg
• .kokoro/presubmit/java8-osx.cfg
• .kokoro/presubmit/java8-win.cfg
• .kokoro/presubmit/java8.cfg
• .kokoro/presubmit/linkage-monitor.cfg
• .kokoro/presubmit/lint.cfg
• .kokoro/presubmit/samples.cfg
• .kokoro/readme.sh
• .kokoro/release/bump_snapshot.cfg
• .kokoro/release/common.cfg
• .kokoro/release/common.sh
• .kokoro/release/drop.cfg
• .kokoro/release/drop.sh
• .kokoro/release/promote.cfg
• .kokoro/release/promote.sh
• .kokoro/release/publish_javadoc.cfg
• .kokoro/release/publish_javadoc.sh
• .kokoro/release/publish_javadoc11.cfg
• .kokoro/release/publish_javadoc11.sh
• .kokoro/release/snapshot.cfg
• .kokoro/release/snapshot.sh
• .kokoro/release/stage.cfg
• .kokoro/release/stage.sh
• .kokoro/trampoline.sh
• codecov.yaml
• java.header
• license-checks.xml
• renovate.json