Add .editorconfig file (#1628)

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+trim_trailing_whitespace = true
+insert_final_newline = true
+charset = utf-8
+
+[*.py]
+max_line_length = 95