Use favicons for standard links instead of default linkace icon

Is your feature request related to a problem? Please describe. Default icon is used for standard links, when favicons could be used.

Describe the solution you'd like Fetch favicons (if present) from sites, and use linkace's default icon as fallback (currently only this icon is used for standard links).

Describe alternatives you've considered

Additional context Favicons make it easier to identify stuff and using the same icon for links makes them harder to tell apart. Even though tags can be used to tell links apart, images are easier to remember.