Add gRPC code from the SDS to the Secret Detection gem

Gemfile.checksum

Gemfile.lock

Gemfile.next.checksum

Gemfile.next.lock

db/structure.sql

...xamples/lib/gitlab/diffs_secrets_check_shared_examples.rb

...ared_examples/lib/gitlab/secrets_check_shared_examples.rb

gems/gitlab-secret_detection/.rubocop.yml

gems/gitlab-secret_detection/Gemfile.lock

gems/gitlab-secret_detection/gitlab-secret_detection.gemspec

gems/gitlab-secret_detection/lib/gitlab/secret_detection.rb

...tlab-secret_detection/lib/gitlab/secret_detection/grpc.rb

...on/lib/gitlab/secret_detection/grpc/client/grpc_client.rb

...secret_detection/grpc/client/stream_request_enumerator.rb

...ction/lib/gitlab/secret_detection/grpc/generated/.gitkeep

...ab/secret_detection/grpc/generated/secret_detection_pb.rb

..._detection/grpc/generated/secret_detection_services_pb.rb

...ab-secret_detection/lib/gitlab/secret_detection/status.rb

...lab-secret_detection/lib/gitlab/secret_detection/utils.rb

...etection/lib/gitlab/secret_detection/utils/certificate.rb