Add spatial WvW informational pop-ups

[SamHurne]

The idea here is to add a new form of WvW pop-ups that display information about objectives as the user moves within a certain distance of an objective.

For example, say the player runs within 100 meters of a camp, and it has 3 minutes of RI left, a message/window would pop-up warning the player.

The distance threshold could be configurable, maybe on a per-objective-type basis.

This is only an initial idea - I'm not sure if it's that useful or helpful yet, but I wanted to throw it on here in case I (or anyone else) has more thoughts on it.