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

java/google/registry/ui/server/registrar/ConsoleUiAction.java

@@ -138,6 +138,7 @@ public final class ConsoleUiAction implements Runnable {
     data.put("xsrfToken", xsrfTokenManager.generateToken(userAuthInfo.user().getEmail()));
     data.put("clientId", clientId);
     data.put("showPaymentLink", registrar.getBillingMethod() == Registrar.BillingMethod.BRAINTREE);
+    data.put("requireFeeExtension", registrar.getPremiumPriceAckRequired());
 
     String payload = TOFU_SUPPLIER.get()
             .newRenderer(ConsoleSoyInfo.MAIN)