Don't have 4 different coordinate systems

[TiaSinghania]

We currently have 4 coordinate systems scattered throughout our code:

• gps (from ins)
• utm
• world (utm but shifted to be convenient for us)
• buggy-relative coordinates

lets not do that
at some point: we should update the code so the node that recieves the ins data (as gps coords) immediately converts to utm and republishes it. (burn world coords). any individual node that needs data can then just subscribe to a single topic and not need to independently do math. depending on how often buggy-relative coords are used we can either republish that in the gps node as well or just let individual nodes deal with it.

[christianvluu]

there's a finepoint that world to UTM isn't necessary a straight linear transformation. World doesn't get zeroed out when we cross between UTM zones. UTM northing and easting will zero out/wrap around when we cross zones. For our purposes, this doesn't matter too much since we lie smack in the middle of a zone. But initially this was done because of two reasons:

1. Flexibility with zone crossing
2. Simulator work (engine.py) began before coordinate system selection. clown leading clowns type behavior since everything was being developed from scratch with nothing to base it on.