Move ROID suffix handling from RegistryConfig to ConfigModule

This is the first in a decently long series of commits to delete RegistryConfig
entirely and centralize all configuration in ConfigModule using Dagger. Once
this is done, then the text-based YAML configuration work can begin in earnest.

Note that the configuration settings from TestRegistryConfig will be moving
into ConfigModule.LocalTestConfig. This way they can be referred to in a static
context from test and test utility helpers, rather than having to be injected
everywhere, which we don't typically bother with for tests.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=143473089

java/google/registry/config/ConfigModule.java

@@ -113,6 +113,19 @@ public final class ConfigModule {
     return "Nomulus";
   }
 
+  /**
+   * Returns the roid suffix to be used for the roids of all contacts and hosts.  E.g. a value of
+   * "ROID" would end up creating roids that look like "ABC123-ROID".
+   *
+   * @see <a href="http://www.iana.org/assignments/epp-repository-ids/epp-repository-ids.xhtml">
+   *      Extensible Provisioning Protocol (EPP) Repository Identifiers</a>
+   */
+  @Provides
+  @Config("contactAndHostRoidSuffix")
+  public static String provideContactAndHostRoidSuffix(RegistryEnvironment environment) {
+    return LocalTestConfig.CONTACT_AND_HOST_ROID_SUFFIX;
+  }
+
   /**
    * The e-mail address for questions about integrating with the registry.  Used in the
    * "contact-us" section of the registrar console.
@@ -1007,4 +1020,10 @@ public final class ConfigModule {
             .build())
         .build();
   }
+
+  /** Config values used for local and unit test environments. */
+  public static class LocalTestConfig {
+
+    public static final String CONTACT_AND_HOST_ROID_SUFFIX = "ROID";
+  }
 }