Replace default export with named exports (#1998)

## Launch Checklist

See title,
Also removed some "_" from some file names.
This is a pure refactoring, no logic changes.


 - [x] Briefly describe the changes in this PR.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/components/InputString.tsx

@@ -20,7 +20,7 @@ type InputStringState = {
   value?: string
 };
 
-export default class InputString extends React.Component<InputStringProps, InputStringState> {
+export class InputString extends React.Component<InputStringProps, InputStringState> {
   static defaultProps = {
     onInput: () => {},
   };