Dedicated module for WMTS request encoding enum

src/ol/source/wmtsrequestencoding.js

@@ -0,0 +1,10 @@
+goog.provide('ol.source.WMTSRequestEncoding');
+
+/**
+ * Request encoding. One of 'KVP', 'REST'.
+ * @enum {string}
+ */
+ol.source.WMTSRequestEncoding = {
+  KVP: 'KVP',  // see spec §8
+  REST: 'REST' // see spec §10
+};