Implement "premium price ack required" checkbox

Implement a checkbox in the "Resources" tab to allow registrars to toggle
their "premium price ack required" flag.

Tested:
  Verfied the console functionality by hand.  I've started work on an
  automated test, but we can't actually test those from blaze and the
  kokoro tests are way too time-consuming to be practical for development, so
  we're going to have to either find a way to run those locally outside of
  the normal process or make do without a test.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=190212177

javatests/google/registry/ui/server/registrar/SecuritySettingsTest.java

@@ -112,7 +112,7 @@ public class SecuritySettingsTest extends RegistrarSettingsActionTestCase {
                 .setClientCertificate(SAMPLE_CERT, START_OF_TIME)
                 .setFailoverClientCertificate(SAMPLE_CERT2, START_OF_TIME)
                 .build());
-    when(sessionUtils.getRegistrarForAuthResult(req, action.authResult))
+    when(sessionUtils.getRegistrarForAuthResult(req, action.authResult, false))
         .thenReturn(initialRegistrar);
     Map<String, Object> jsonMap = initialRegistrar.toJsonMap();
     jsonMap.put("clientCertificate", null);