Add fields for route relations

[mfbehrens99]

Additional fields that would by handy:

• distance
• duration
• ascent/descent
• roundtrip (= yes/no)
• maybe colour

[maro-21]

distance, duration and colour are already there

[quincylvania]

@mfbehrens99 Okay, I added fields for ascent, descent, and roundtrip to the pertinent route presets. We already support the other fields.

Note that iD has limited fields for the generic type=route preset since we can't be sure the fields will be relevant to all kinds of routes. For example, roundtrip doesn't really make sense for utilities.