Add WHOIS disclaimer text to ConfigModule

This fixes #23 for @parsoj by allowing a custom disclaimer to be
specified via dependency injection modules.

By making the disclaimer part of the dependency injection graph, it can
come from anywhere.

For example, if I was Donuts, I would have my own repository. I'd use an
external http_archive() repository for Domain Registry. Then I would
write my own Dagger @Component for each App Engine module. My Component
would have a list of Dagger Modules, which I copied from the Domain
Registry version. Then I would swap out ConfigModule with my own
DonutsConfigModule, which provides the same values.

So long as a method exists that @Provides @Config("whoisRegistry"), and
the module containing it is listed in the @Component, the dependency
injection graph becomes valid and complete for the whois package
(provided other dependencies are met.)

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128082921

java/google/registry/whois/WhoisException.java

@@ -60,11 +60,11 @@ public final class WhoisException extends Exception implements WhoisResponse {
   }
 
   @Override
-  public String getPlainTextOutput(boolean preferUnicode) {
+  public String getPlainTextOutput(boolean preferUnicode, String disclaimer) {
     return new WhoisResponseImpl.BasicEmitter()
         .emitRawLine(getMessage())
         .emitLastUpdated(getTimestamp())
-        .emitFooter()
+        .emitFooter(disclaimer)
         .toString();
   }
 }