Properties with underscores

[DavidBruchmann]

Describe the bug
Properties are requested with underscores instead of camelCase in the builder module and they are created with underscores in the models too, like $my_property.
This clashes certainly with extbase and should be changed back, like it was before.

To Reproduce
Steps to reproduce the behavior:

1. Go to any model in the builder module and try to enter a property in camelCase
2. see: upper case is not allowed there
3. create property with underscore instead, and save
4. See underscore in the created model file

Expected behavior
That properties are created extbase compatible with camelCase

TYPO3 Version
v12

Extension Builder Version:
Git-branch or TER version?
v12

[DavidBruchmann]

might be duplicate of #730