Add EditorConfig file

ref [EditorConfig](https://editorconfig.org/)
followup or may help #3349 #3280 ;-)

Author: stoned

.editorconfig

@@ -0,0 +1,11 @@
+root = true
+
+[*]
+charset = utf-8
+
+[*.pod6]
+indent_style = space
+indent_size = 4
+insert_final_newline = true
+trim_trailing_whitespace = true
+max_line_length = 72