Multiple terrain changes and fixes for maps (#4502)

## Description:

Multiple changes for maps:

Mississippi - Fix some landlocked lakes, near the main coast. Players
would sometimes accidentally put a port in the dead lakes

North America - Re-add the Azores and Cape verde (accidentally removed
when the map generator got updated to delete small islands)

Africa - Re-add Ascencion and Saint Helena Islands, same case as NA

Danish Straits - replace german empire flag , as agreed in the leads
channel

Giant World Map - Coast fixes, including adding Suez Canal which greatly
affected trade routes

Great Lakes - fix landlocked lake

Two Lakes - New Terrain combining both old and recent versions

World - Add strait of malacca

## 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

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

tri.star1011

map-generator/assets/maps/twolakes/info.json

@@ -3,7 +3,7 @@
   "name": "Two Lakes",
   "translation_key": "map.twolakes",
   "categories": ["europe"],
-  "multiplayer_frequency": 6,
+  "multiplayer_frequency": 4,
   "nations": [
     {
       "coordinates": [1025, 750],