pioneer: restore the .editorconfig

pioneer/.editorconfig

@@ -0,0 +1,10 @@
+root = true
+[*]
+indent_style=space
+indent_size=2
+tab_width=2
+end_of_line=lf
+charset=utf-8
+trim_trailing_whitespace=true
+max_line_length=120
+insert_final_newline=true