Make the "Generic > metric" widget more visible in the dashboard #14612

A super valuable feature is the ability to add a KPI to the dashboard. It's hidden under Generic > Metric:

Instead:

• could we maybe rename Generic to KPI Metric
• could we rename Metric to KPI Metric
• move this to be the first entry in the list, above Visitors

This way it will be more visible to users that they can add any KPi to their users.