Add support for hwy and freeway exits as intersections

[mraross]

Highway and freeway exits should be recognized as a type of intersection by the geocoder and route planner since they are part of the road network.
BC Wildfire Service Fire Reporting Centre needs to be able to find a location by hwy exit number.

There are a couple of ways to do this:

1. Extend ITN data prep to create the appropriate exit street aliases.
2. Extend the definition of Intersection to support exits.

Option 1 seems simpler at this point.

1. In ITN data prep, create street aliases for off-ramps in the following form:

   Hwy <routeNo> and Exit <exitNo>
   

Here's an example:

        Hwy 1 and Exit 305

This form doesn't distinguish between the two directions of travel (e.g., NorthBound/ SouthBound) This would require an addition as in:

               Hwy <routeNo> and Exit <exitNo> <direction>

and here's another example:

               Hwy 1 and Exit 305 Eastbound

With this intersection format you can enter:

                Hwy 1 and exit 305

and the geocoder in autocompletion mode should return:

                Hwy 1 and Exit 305 Eastbound
                Hwy 1 and Exit 305 Westbound

[cmhodgson]

I think a slight clarification is required, for (1) the street alias is not Hwy <routeNo> and Exit <exitNo> but simply Exit <exitNo>, and this alias is applied to all segments of the offramp/exit. The result of this is that you can search for an intersection using the string Hwy <routeNo> and Exit <exitNo> because of the Exit <exitNo> alias on the street segments.

[cmhodgson]

For now we will only add the exit <#> alias to the exit segment. We will not worry about the -bound or "to wherever" part of this problem at this time.

[mraross]

So assuming hwy 1 has an exit 305, please confirm after this enhancement, the geocoder will be able to match the following intersection:

HWY 1 and Exit 305 

It should actually return more than one match since there are eastbound and westbound exit 305s.

[gleeming]

While there is no exit 305 in BC, for exit 366 in Kamloops at Copperhead Dr, yes there should be two Hwy 1 and Exit 366 intersection points generated with this enhancement.

Quality of data will be based on what is in ITN. There will likely be a few segments that need updating to add or remove exit attribution in order to fix issues.

[mraross]

Verified in v4.1 gold in Test using Hwy 1 and Exit 366.