feat(NcPasswordField): allow to set visibility state

[susnux]

☑️ Resolves

Allows to programmatically set the obfuscation state of the password.
This is useful e.g. to hide the password in some cases, like submitting the login form.

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable
• 2️⃣ Backport to stable8 for maintained Vue 2 version or not applicable

[susnux]

/backport to stable8

[kesselb]

Thank you for picking it up 🙏

Using "v-model:obfuscated" is much nicer than modifying the state directly. ;)

[Antreesy]

LGTM. Make sense to put it in changelog notes?

[susnux]

obfuscated ( ❤️ ) vs visible ( 🚀 ) for the property name?

[susnux]

Lets go with visible, even if I think obfuscated is also a good name, its better to stick with boolean values that default to false - in this case it would be non-obfuscated or we inverse it and just use visible.