* UX: update styling for related/suggested
This PR addresses state issues for icons of the Related & Suggested buttons, as well as well as fixes alignment issues for folding phones / tablets, wider mobile devices by moving styling to the desktop scss file; also replaces border with box-shadow.
* UX: update styling for related/suggested
This PR fixes styling for previous related/suggested changes' positioning being off for topics and updates the active icon color by removing a line that changed its active color.
This PR updates the styling for the related & suggested topics to distract less from the Reply buttons and clearly indicate its usage as tabs, also referred to as pills.
This PR changes how we track which lists are available for a topic and how we decide which is the active one. The new approach centralizes everything in the service, and exposes functions for adding/removing a list, which each calls via `did-insert/will-destroy` modifiers.
It makes it much easier to track and update state when navigated to another topic or PM, ensuring things get updated correctly.
