Make puck invisible until the first location fix

[LukasPaczos]

Refs. #458 (review).
The location is displayed before we get the first location fix resulting in the puck being displayed at the null island.

[cammace]

I'm reopening this and reverting PR #476 since this causes the location layer source to not get re-added to the map when the map styles changed resulting in a bunch of source not found logging.

[cammace]

Plan moving forward on this will be to create an additional constructor which doesn't take in a LocationEngine. In this case, we would call obtainBestLocation and setup the engine ourselves.

[lilykaiser]

Do we need a UI prompt before location updates happen?