Add Finland network logic

[nvkelso]

We have shield artwork for Finland's roads, but no network values because the data is sparse there so we need to compute values.

These are the 4 classes, adapt to match other FI:*-road convention.

• FI:FI National road (primary) Red rounded rectangle
• FI:FS Secondary road - Yellow rounded rectangle
• FI:RR Regional – White rounded rectangle
• FI:LR Local road - Blue rounded rectangle