This adds the option of showing 4 latest histories in Multiview,
instead of always tracking pinned histories. Once the user decides
to track pinned histories, we do so, until the user "resets" it to
recent histories mode.

Also organized the multiple histories in Multiview to show up evenly,
with the `HistoryDetails` taking up a fixed space at the top.

Refactored `SelectorModal` to use the new history scroll list in it.
Also, prevented `Upload` activity in activity bar from toggling out the current sidepanel.

…ll list

If no pinned histories, we are in "show recent mode" and the new history will be appended to the beginning of the view.

Alter the way the `ActivityBar` treats "panel activities";
i.e.: activities that have a sideBar associated,
so that if the sidebar is active but the current route isn't `activity.to`, then keep sidebar active and
just change route.

Also, if `activity.to` is current route, always keep activity's `is-active` prop = true regardless of sidebar for the activity being active or not.

This adds an upper div to the `.history-picker` which can be clicked to create and pin a new history.

Also added `keydown` events for tab accessibility

Adjust classes to make all activity panels look uniform

This caused a jest to fail because we tried to access the `filtered` computed array before it was even initialized.

Co-authored-by: Alireza Heidari <[email protected]>

Co-authored-by: Alireza Heidari <[email protected]>

Also, use imported icons instead of string icons for `FontAwesomeIcon`s