teacher tool - don't default export components

[eanders-ms]

In the interest of long-term code maintainability, prefer not to use default export unless there is a compelling reason for it. Default exports have a few gotchas that I'd like to avoid:

• The name assigned to the import can be anything, and doesn't reflect what you're actually importing.
• They're not discoverable by IntelliSense. You have to open the file to see what you're actually importing. The filename isn't a reliable source of information.
• During the inevitable refactor/renaming, you must search the code and manually update every import to match the new component name. The compiler can't help you.

Sometimes a default export is the appropriate pattern to employ, but let's not make them the default export pattern we employ. (Did I break your parser? :))

[srietkerk]

Thanks for the explanations of the downfalls of export default, it's super helpful!