Adds Northwest Passage map (using new additionalNations feature) (#3920)

## Description:

Adds map "Northwest Passage", map of the Canadian Arctic Archipelago ,
Greenland and surroundings. "Northwest Passage" (NWP) is the sea lane
between the Atlantic and Pacific oceans
(https://en.wikipedia.org/wiki/Northwest_Passage) .

21 default nations, based on the towns of the region.

This map uses the brand new additionalNations feature made by FloPinguin
https://github.com/openfrontio/OpenFrontIO/pull/3902 . Adds 39 extra
nations for a total of 60 nations (so that in gamemodes like Humans vs
Nations all the nations have names of real places)

Comparison: 
- Map with default nations
- Map with extra named nations, tested by raising the number of nations
in Solo

<img width="1050" height="412" alt="image"
src="https://github.com/user-attachments/assets/12ed94f1-0615-4fb3-b0d0-dcecb65006ea"
/>
<img width="1089" height="436" alt="image"
src="https://github.com/user-attachments/assets/6e7c11bf-7382-4e36-9433-229a9d463b68"
/>

Terrain source from OpenTopography, already credited in CREDITS.md

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

tri.star1011

src/server/MapPlaylist.ts

@@ -82,6 +82,7 @@ const FREQUENCY: Partial<Record<GameMapName, number>> = {
   NewYorkCity: 3,
   NileDelta: 4,
   NorthAmerica: 5,
+  NorthwestPassage: 5,
   Pangaea: 5,
   Passage: 4,
   Pluto: 6,