Fix archetype file renaming using standard Maven approach

- Add gitignore and github properties to archetype-metadata.xml
- Set filtered=true for __gitignore__ to enable token replacement
- Remove unnecessary post-generation script
- Files are now properly renamed from __gitignore__ to .gitignore and __github__ to .github

Author: Ben Asmussen

src/main/resources/META-INF/archetype-post-generate.groovy

@@ -21,6 +21,12 @@
         <requiredProperty key="javaVersion">
             <defaultValue>17</defaultValue>
         </requiredProperty>
+        <requiredProperty key="gitignore">
+            <defaultValue>.gitignore</defaultValue>
+        </requiredProperty>
+        <requiredProperty key="github">
+            <defaultValue>.github</defaultValue>
+        </requiredProperty>
     </requiredProperties>
 
     <fileSets>