NethVoice CTI: create new phone-island token for NethLink

[edospadoni]

Allow creation of non-expiring token for NethLink using subtype attribute

We need to generate a non-expiring token for NethLink, similar to the one used by the web interface. This feature is necessary to allow background services or integrations to authenticate without requiring periodic renewal of the token.

Proposed solution

Introduce the ability to create a token with no expiration when the subtype is set to nethlink. This will allow us to distinguish it from a regular web token and apply different logic, such as skipping expiration checks.

Additional context

The same logic is already used for the web subtype. Extending it to nethlink would ensure consistency and minimal implementation effort.

[edospadoni]

Test case:

• Go to Settings → Integrations and generate a token for Phone-Island
• Copy the token and use it for an external integration, in an HTML page or on Storybook, and make sure it works
• Log in to NethLink and ensure that the previously created token for the integration continues to work

[edospadoni]

Testing release:

• ns8-nethvoice: https://github.com/nethesis/ns8-nethvoice/releases/tag/1.3.4-testing.21
• nethlink: feat(token): added subtype in phone-island nethlink#65 (comment)