Git ignore all IntelliJ files (apache#156)

Co-authored-by: Ken Dombeck <ken.dombeck@target.com>

Author: kdombeck

.gitignore

@@ -17,4 +17,9 @@ site-content
 /.classpath
 /.project
 /.settings/
-/commons-cli.iml
+
+### IntelliJ IDEA ###
+.idea/
+*.iws
+*.ipr
+*.iml