This patch is a follow-up to D2933/rP24016. It does the following:
* Removes the tower-like <Attack> and <BuildingAI> from the outpost, and instead gives it a <TurretHolder> (i.e. visible garrison slot) and <Auras>, like walls.
* Removes the now unnecessary garrison flags from the various outpost actors.
* Corrects footprint, rubble, obstruction, status bar, and foundation sizes of the outpost template.
* Because outposts are now differentiated from towers, they no longer need to inherit from `template_structure_defensive_tower.xml`, therefore `*_outpost.xml` is renamed to `template_structure_defensive_outpost.xml`.
* Updates all specific outpost templates accordingly.
How it looks in game: {F1540345}