[FR]: Set an external tool(s) to open URLs from specific domains by default

[RetroAbstract]

Brief description of the feature request

This feature would allow the user to set links from one or multiple URL domains to be opened by a specific external tool by default when double clicking said links.

For example if the user wanted RSS Guard to automatically open Youtube links with the command prompt when double-clicking them in RSS Guard, and automatically open any other URLs in their article list with the default external browser they had already set, they would be able to do so by adding Youtube's domain in a "Domain(s)" prompt box following the already existing "Parameters" prompt when adding cmd.exe as an external tool.

In the external tools menu this would result in a "Domain(s)" column added, displaying what URL domains the user added to be associated with different external tools by default.

The user would be able to add multiple URL domains to be opened by an external tool by default by separating the URLs with commas.