How to restore the panel with viewport navigation tools I remember there being a panel with buttons to zoom in or out or pan in the viewport but it seems to have gone somehow. How can I add it back?
The tabs on the toolbar come from addons, if one is missing then the addon that put it there has been disabled or uninstalled.

The steps you list are available using the mouse and keyboard, use &#8679; Shift MMB to pan, the  scroll wheel as well as &#9096; Ctrl MMB will zoom in/out.