Re-add cannon direction for vertical cannons (mortars)

[goodroach]

I know this was a removed feature from cannon directors, but I would prefer if we can toggle if the cannon directors can direct mortars or not rather than outright removing the feature.

[goodroach]

Additionally, it could just be a seperate director that would only work on vertically launched cannons named "Mortar director" which only directs vertical cannons.