Make 'Anonymous Coward' configurable

Make the username that is displayed for users that haven't set a full
name configurable.

'Anonymous Coward' that was hard-coded in Gerrit before was seen by
some users as unprofessional and insulting. This is why for corporate
environments it makes sense to configure another name.

Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
Change-Id: Ib2edee2af342b17df676e87cef99f92448895abe

gerrit-server/src/test/java/com/google/gerrit/server/mail/FromAddressGeneratorProviderTest.java

@@ -47,7 +47,8 @@ public class FromAddressGeneratorProviderTest extends TestCase {
   }
 
   private FromAddressGenerator create() {
-    return new FromAddressGeneratorProvider(config, ident, accountCache).get();
+    return new FromAddressGeneratorProvider(config, "Anonymous Coward", ident,
+        accountCache).get();
   }
 
   private void setFrom(final String newFrom) {