ModelSelect2Widget: if no result was found, use the entered text for form submit

[Zerotask]

Is your feature request related to a problem? Please describe.
I want to search for existing companies and if no company was found, I want to use the entered text for the form submit, to create a new company.

Describe the solution you'd like
A new option so users can use/selected their entered text, if no results were found.

Describe alternatives you've considered
using 2 form fields, one for the select and the other for a regular CharField.

Additional context
Add any other context or screenshots about the feature request here.