Add GenerateSpec11Action and SafeBrowsing evaluation

This adds actual subdomain verification via the SafeBrowsing API to the Spec11
pipeline, as well as on-the-fly KMS decryption via the GenerateSpec11Action to
securely store our API key in source code.

Testing the interaction becomes difficult due to serialization requirements, and will be significantly expanded in the next cl. For now, it verifies basic end-to-end pipeline behavior.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=208092942

java/google/registry/keyring/api/Keyring.java

@@ -115,6 +115,13 @@ public interface Keyring extends AutoCloseable {
    */
   String getRdeSshClientPrivateKey();
 
+  /**
+   * Returns the API key for accessing the SafeBrowsing API.
+   *
+   * @see google.registry.reporting.spec11.GenerateSpec11ReportAction
+   */
+  String getSafeBrowsingAPIKey();
+
   /**
    * Returns password to be used when uploading reports to ICANN.
    *