Rename WhoisServer and WhoisHttpServer to actions

These servlets are converted to actions during daggerization. Calling them servers are misleading.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=190942237

javatests/google/registry/whois/WhoisTestComponent.java

@@ -30,6 +30,7 @@ import javax.inject.Singleton;
     WhoisModule.class,
 })
 interface WhoisTestComponent {
-  WhoisHttpServer whoisHttpServer();
-  WhoisServer whoisServer();
+  WhoisHttpAction whoisHttpAction();
+
+  WhoisAction whoisAction();
 }