Add "Domain target" column for external links and create Views display to group and count domains

Problem/Motivation

The current system lacks visibility into the domain targets of external links listed in the main table. Users cannot easily identify which external domains are being linked to without inspecting the full URLs manually.

Additionally, there is a need for a dedicated Views display to group external link targets by domain and count the number of times each domain appears on the site. This would support better analysis, moderation, or reporting of external link usage and iframes.

Steps to reproduce

• Navigate to the main table that lists links (possibly a View displaying content or link entities).
• Observe that the column for external links displays the full URL but does not isolate or highlight the domain.
• Try to analyze which external domains are most frequently used — no summary or domain-level aggregation is available.

Proposed resolution

Add a new column to the existing View (main table):

• Label: Domain target
• Content: Extract and display the domain of the URL, only for external links.
• Logic should ensure internal links are excluded or shown as empty/null in this column.

Create a new Views display:

• Name: Domains
• Description: Group external links by domain and provide a count of how many times each domain is referenced.

Remaining tasks