style: add .editorconfig

See https://editorconfig.org/#example-file

.editorconfig

@@ -0,0 +1,31 @@
+root = true
+
+[*]
+charset = utf-8
+trim_trailing_whitespace = true
+
+[*.{cpp,c,hpp,h,py}]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+insert_final_newline = true
+
+[*.dart]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+insert_final_newline = true
+
+[*.{java,m,md}]
+indent_style = space
+end_of_line = lf
+insert_final_newline = true
+
+[*.json]
+indent_style = space
+
+[{*.sh,Makefile}]
+indent_style = tab
+indent_size = 4
+end_of_line = lf
+insert_final_newline = true

src/ui/flutter_app/intl_arb2csv.py

@@ -20,4 +20,4 @@ with open(csv_file_path, mode='w', encoding='utf8') as csv_file:
     fieldnames = ['key', 'string']
     writer = csv.DictWriter(csv_file, fieldnames=fieldnames)
     for key in list(intl_dict):
-        writer.writerow({'key': key, 'string': intl_dict[key]})
+        writer.writerow({'key': key, 'string': intl_dict[key]})