NethLink: Add customizable keyboard shortcut to start calls

[mgarra]

Description:

It would be useful to implement the ability to start a call after selecting a phone number using a keyboard shortcut. This shortcut should be customizable to allow users to set their preferred key combination.

Feature request details:

• The user selects a phone number.
• A keyboard shortcut triggers the call initiation.
• The shortcut should be configurable in the settings.

Benefits:

• Improves efficiency by reducing the need for mouse interactions.
• Enhances accessibility for power users who rely on keyboard shortcuts.
• Provides flexibility with customizable key combinations.