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/InputCheckbox.tsx

@@ -6,7 +6,7 @@ export type InputCheckboxProps = {
   onChange(...args: unknown[]): unknown
 };
 
-export default class InputCheckbox extends React.Component<InputCheckboxProps> {
+export class InputCheckbox extends React.Component<InputCheckboxProps> {
   static defaultProps = {
     value: false,
   };