NV: Clark County truncations

[cl94]

I was looking through NDOT data/logs today and noticed several truncations in the Las Vegas area. These include the west end of NV 147, the west end of NV 574, the north end of NV 582, and the north end of NV 596. I removed these segments from the browser as part of other housekeeping around Vegas and they'll be in the next update.

Of course, further truncations/deletions on surface roads in Clark County are likely once the 215 swap happens next year, so pay attention to this space.

https://github.com/TravelMapping/HighwayData/pull/6915