Document bridge installation and setup

While setting up a more permanent bridge in 3.2, we need to improve our documentation (https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/conjure/-/wikis/wireguard-setup) for this process. This bridge is being operated internally by staff at the Tor Project right now, but it would be ideal for decentralization to engage a volunteer to operate this bridge. To pass this work to a volunteer, we need good documentation. This documentation will also be helpful so that when new ISPs opt-in to collaborate, they have clear instructions.