Add mvn settings

These should allow deployment credentials to be obtained from the local environment variables

.mvn/local-settings.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
+          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+          xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
+    <proxies>
+    </proxies>
+    <servers>
+        <server>
+            <id>ossrh</id>
+            <username>${env.OSSRH_USERNAME}</username>
+            <password>${env.OSSRH_PASSWORD}</password>
+        </server>
+    </servers>
+</settings>