Use Multimap bindings to construct BigQuery schema map

This refactoring allows the schemas to live in the same package they
are used, rather than all having to be inside the bigquery package.
This is a follow-up to []
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=120551011

java/com/google/domain/registry/bigquery/BigqueryModule.java

@@ -21,12 +21,16 @@ import com.google.api.client.http.HttpTransport;
 import com.google.api.client.json.JsonFactory;
 import com.google.api.services.bigquery.Bigquery;
 import com.google.api.services.bigquery.BigqueryScopes;
+import com.google.api.services.bigquery.model.TableFieldSchema;
+import com.google.common.collect.ImmutableList;
 import com.google.domain.registry.config.ConfigModule.Config;
 import com.google.domain.registry.request.OAuthScopes;
 
 import dagger.Module;
+import dagger.Multibindings;
 import dagger.Provides;
 
+import java.util.Map;
 import java.util.Set;
 
 /**
@@ -41,6 +45,13 @@ import java.util.Set;
 @Module
 public final class BigqueryModule {
 
+  @Multibindings
+  interface BigQueryMultibindings {
+
+    /** Provides a map of BigQuery table names to field names. */
+    Map<String, ImmutableList<TableFieldSchema>> bigquerySchemas();
+  }
+
   /** Provides OAuth2 scopes for the Bigquery service needed by Domain Registry. */
   @Provides(type = SET_VALUES)
   @OAuthScopes