[Form] Automated label generation for forms

| Q             | A
| ------------- | ---
| Bug fix?      | [no]
| New feature?  | [yes]
| BC breaks?    | [no]
| Deprecations? | [no]
| Tests pass?   | TBD
| Fixed tickets | Not a fix, but discussed in #11298
| License       | MIT
| Doc PR        | TBD
| standard edition PR        | TBD
Discussion started in #11298

This PR is about adding an option to automate the label generation for forms:

```yaml
# app/config/config.yml
framework:
    form:
        # auto_label: ~                      # enable the extension
        # auto_label: form.%%type%%.%%name%% # set the auto_label globally, but allow overriding per form
```

This option would be useful for big I18Ned applications with standardized label form translations. We could also add an option for a default **translation_domain**.

```yaml
    form:
        translation_domain: "form"
```

I started this work as a third-party extension, because most applications don't need it, so the footprint is null for them.

What is your advice on it?

- [x] Inherit auto-label from parent
- [ ] Create the documentation PR
- [ ] Create the standard edition PR

Should be ``null === $options['label']`` (also in the expressions below).