Smear out DNS updates over time when updating DNS for all domains

These updates can generally ran slowly in the background (i.e. they're low
priority), and shouldn't clog up the system to the point where they slow down
live incoming customer-requested updates.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=250732171

java/google/registry/tools/server/ToolsServerModule.java

@@ -108,4 +108,10 @@ public class ToolsServerModule {
   String provideJobId(HttpServletRequest req) {
     return extractRequiredParameter(req, "jobId");
   }
+
+  @Provides
+  @Parameter("smearMinutes")
+  static int provideSmearMinutes(HttpServletRequest req) {
+    return extractIntParameter(req, "smearMinutes");
+  }
 }