SVWD03: Give trunk roads their own colo(u)r

[IloveRumania]

Currently, trunk roads (and _links) are colo(u)red light red (the same as highway=primary, I think) with a darker red outline. They should have their own colo(u)r to make them distinct. Since the colo(u)rs of the other highways appear to be based on JOSM's default preset, I suggest using light(ish) green. Thank you!

[SomeoneElseOSM]

Historically, the map style that evolved into this one (at least as far as colours are concerned) had green trunk roads. That changed (on the OSM website) in 2015 - see this blog post from the time: https://blog.openstreetmap.org/2015/10/30/openstreetmap-org-map-changing/ . I had previously changed trunk from green in July of the same year: SomeoneElseOSM/openstreetmap-carto-AJT@467f057 .

The problem with green for trunk roads is that it can be difficult to see over other green features such as wood/forest - such as here: https://www.openstreetmap.org/#map=14/57.50365/13.69506&layers=S . That shows forest and scrub.

Please do feel free to experiment with what colour you think might work. If you can choose a colour and want to see what it looks like but can't test the style locally let me know the hex codes for the fill and the casing (various websites such as https://htmlcolorcodes.com/color-picker/ can generate those) and I can post a picture of what it would look like.