refactor(): add *.module.ts files

[danielsogl]

If you want to use lazy loading, it would be great if you can start doing this, without creating the module.ts files by yourself.

[c-t-n]

Please accept this PR, this would save a lot of time for newcomers with Ionic. 🙏

[DavidFrahm]

I'm curious if people think lazy loading should be the default for tabs. Given that's the main content, eager loading might be preferred.

I know just enough about this to be dangerous, so feel free to give a quick explanation of the "why" and move on ;)

[danielsogl]

cc @brandyscarney