Figure out how to expose `tor-ptmgr`'s APIs
The 1.1 release included what was necessary to get PTs working with the arti
binary, but we haven't actually figured out a nice API to expose to users calling the tor-ptmgr
crate directly, since there wasn't time.
A particular example @Diziet mentioned was "small CLI tool that lets someone easily check whether their proxy is up or not" (apparently a real user's usecase).