Update ruleset, add ruleset factory test

Using pmd.website.baseurl parameter

pmd-kotlin/pom.xml

@@ -16,7 +16,6 @@
     </properties>
 
     <build>
-        <!-- needed for pmd sonar plugin -->
         <resources>
             <resource>
                 <directory>${project.basedir}/src/main/resources</directory>

pmd-kotlin/src/main/resources/category/kotlin/bestpractices.xml

@@ -10,12 +10,11 @@ Rules which enforce generally accepted best practices.
     </description>
 
     <rule name="FunctionNameTooShort"
-          since="7.0"
+          since="7.0.0"
           language="kotlin"
           message="Function names should have non-cryptic and clear names."
           class="net.sourceforge.pmd.lang.rule.XPathRule"
-          typeResolution="true"
-          externalInfoUrl="https://pmd.github.io/pmd/pmd_rules_kotlin_bestpractices.html#functionametooshort">
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_kotlin_bestpractices.html#functionametooshort">
         <description>
             Function names should be easy to understand and describe the intention. Makes developers happy.
         </description>

pmd-kotlin/src/test/java/net/sourceforge/pmd/lang/kotlin/RuleSetFactoryTest.java

@@ -0,0 +1,10 @@
+/*
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang.kotlin;
+
+import net.sourceforge.pmd.AbstractRuleSetFactoryTest;
+
+public class RuleSetFactoryTest extends AbstractRuleSetFactoryTest {
+}