fixes #92 Add a default service.yml so users won't need to customize it

Author: stevehu

src/main/resources/config/service.yml

@@ -0,0 +1,12 @@
+# this is the default service.yml for the lambda-native.
+singletons:
+  - com.networknt.registry.URL:
+    - com.networknt.registry.URLImpl
+  - com.networknt.registry.Registry:
+    - com.networknt.registry.support.DirectRegistry
+  - com.networknt.balance.LoadBalance:
+    - com.networknt.balance.RoundRobinLoadBalance
+  - com.networknt.cluster.Cluster:
+    - com.networknt.cluster.LightCluster
+  - com.networknt.cache.CacheManager:
+    - com.networknt.cache.CaffeineCacheManager