Extend the 'hidden paths' feature to taxonomy

Description of the need

Backdrop has a 'hidden paths' feature for nodes whereby you can disable access to a node's /node/[nid] page from unauthorised users. Basically D7's Rabbitt Hole module in core. However, Backdrop's implementation only applies to nodes. Rabbitt Hole allowed you to hide other entities too, like taxonomy terms.

Proposed solution

Make Backdrop's 'hidden paths' feature apply to taxonomy terms too.

Alternatives that have been considered

Rabbitt Hole has been ported to Backdrop, and looks to be largely unchanged, despite part of the functionality being in Backdrop core now...