Creates a setting under Game Options/Gameplay for selecting the
first escort that will spawn.

This is intended to allow players to make characters that rely on a certain
escort reward without having to reroll repeatedly or savescum to get what they
need, but not gain the advantage of selecting ALL the escorts to get the best
possible reward every time. With this addon, only the first escort to spawn
will be of the selected type; all others will be randomly selected.

An advantage of this over addons that allow selecting the escort type when it
spawns is that it is less likely to cause bugs. This addon does not create a
new in-game menu, but rather handles selection through the settings menu.
Escorts are generated using the standard quest code.