This adds a small module for configuring the trezor-bridge service,
trezord. This service enables users to interact with their Trezor
hardware wallet through the trezor suite web interface, or to use the
device for U2F auth, SSH login, GPG or password mgmt.
https://trezor.io/learn/a/what-is-trezor-bridge
The options were copied directly from the nixos service module here:
9d6e454b85/nixos/modules/services/hardware/trezord.nix (L16)
The implementation was adapted from the nixos module's systemd service
to a launchd user agent.
Tested successfully locally on an Air M2.
