Adds button to view data for a route in LabelMap

[misaugstad]

Resolves #3694

Adds a button after you finish creating a route in RouteBuilder to view the data for just that route in LabelMap. This is done via a URL parameter, so you view data for any route (or routes) at any time. The URL might look like /labelMap?routes=12,8,44 or simply /labelMap?routes=12.

Before/After screenshots (if applicable)

Before

After

And in LabelMap

And then in LabelMap if you selected multiple routes

Things to check before submitting the PR

• [x] I've written a descriptive PR title.
• [x] I've added/updated comments for large or confusing blocks of code.
• [x] I've included before/after screenshots above.
• [x] I've asked for and included translations for any user facing text that was added or modified.
• [x] I've updated any logging. Clicks, keyboard presses, and other user interactions should be logged. If you're not sure how (or if you need to update the logging), ask Mikey. Then make sure the documentation on this wiki page is up to date for the logs you added/updated.

[jonfroehlich]

Super cool. Thanks @misaugstad!