Redwood: Custom Icons in Activity Feed panel to filter Activity Types

Summary:

Redwood: How can we implement Icons in Activity Feed panel under objects like Opportunity, contacts, accounts, leads to filter Activity Types
For example, in the sample image below, how can we implement highlighted icons under Opportunity object in Activity Feed Panel (or custom panel if Activity Feed cannot be customized)? One icon to filter appointments, another to filter tasks etc. Also, is there any OOTB configuration available for this?

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