[CLI] `lb4` does not create app with uppercase letters

@javiersantossanchez arbeitet bereits daran.

Seit 12.10.2020.

## Description / Steps to reproduce / Feature proposal

```sh
$ lb4 myLB4app
> Generation is aborted: Invalid npm package name: myLB4app
```

This is likely due to the `package.json`'s `name` format restriction. We should use the user-submitted name for everything (directory name etc.), except for the `name` property in `package.json`; for that, CLI should do the hyphenation and lowercasing for the user.

Thoughts?

## Current Behavior

`lb4` refuses to create an app if it contains uppercase letters.

## Expected Behavior

Should allow creation of apps with uppercase and lowercase letters.

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