Rename Route.url to Route.path

[meshy]

https://example.com/foo?bar
^^^^^^^^^^^^^^^^^^^^^^^^^^^ <- URL
^^^^^^^^                    <- protocol
        ^^^^^^^^^^^         <- hostname
                   ^^^^     <- path
                       ^^^^ <- query

What we're actually representing with the url field is actually a path. We should rename it.

Thanks to @ghickman for pointing this out, and for the ascii-art.