Add Building Markers

[ampersand38]

When merged this pull request will:

• Add the Building Marker attribute to building objects to add or remove marker from editable buildings, multiple at a time
• Add setting to create building markers when placing buildings
• Marker updates when building is moved
• Marker is deleted if building is deleted
• https://youtu.be/ZjzdFPfDdwQ

[Kexanone]

As I mentioned on Discord, I don't really see a use case for enabling markers for individual buildings. I think it makes more sense to have a global setting for it.

[mharis001]

Do the markers update (position) if the building is moved by Zeus?

[ampersand38]

Not currently. That would definitely be needed for the setting, but wasn't in the workflow I had in mind. (Now it does!)

[mharis001]

The code for this feature is spread out over 3 components. Let's consolidate all of this functionality in a new component for better maintainability - maybe building_markers.

[ampersand38]

Having an issue where placement preview is making the marker spawn at [-1000, -1000], and then CuratorObjectEdited is not being triggered.

[mharis001]

I think this is mostly good and a nice useful feature. Just needs some cleanup.

[mharis001]

I did some minor cleanup and fixes. Building markers were being created for all objects when the placement preview was enabled. Also, changed the marker size calculation to take the difference between the two bounding box extremes.

@ampersand38 Please look my changes over and merge when ready.