Set low `priority` for `fasttravelfromindoors.esp`.

The mod doesn't do any actual content changes, merely changing some
flags that determine whether it's possible to fast travel from a
location or not. Mods that override the cells in more significant ways
should not have their cell changes overridden by this.
Add data for `FastTravelIndoors.esp`.

http://www.nexusmods.com/fallout3/mods/7624