Introduce the org.springframework.geode.util.GeodeConstants class to encapsulate common Apache Geode constants used by SBDG.

The GeodeConstants class will help in the effort to remove all uses of internal Apache Geode APIs, isolating all internal Apache Geode API usage to the apache-geode-extensions module.

Resolves gh-70.

apache-geode-extensions/src/main/java/org/springframework/geode/util/GeodeConstants.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package org.springframework.geode.util;
+
+import org.apache.geode.management.internal.security.ResourceConstants;
+
+/**
+ * The GeodeConstants class...
+ *
+ * @author John Blum
+ * @since 1.0.0
+ */
+public abstract class GeodeConstants {
+
+	public static final String USERNAME = ResourceConstants.USER_NAME;
+	public static final String PASSWORD = ResourceConstants.PASSWORD;
+
+}