UT: 1-15BLBri and I-84BLBri unsigned

[terminal_moraine]

Drove the length of the I-15/I-84 business loops around Brigham City, UT last week.  There were no green shields at any point on the route; nor were there any green shields indicated on exit signage from I-15/I-84.  The loop was only signed as US 91 and UT 13.

I suggest that these routes be removed from the system.

[ntallyn]

Oddly, I was through there last week, as well, and can confirm the lack of signage.

[Duke87]

Based on lack of signage I am deleting both of these routes.

https://github.com/TravelMapping/HighwayData/pull/2106