Add Halkidiki Map (#799)

## Description:
This PR adds the Halkidiki map. It's a region in Greece with rich
history that is very popular also with tourism.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

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

<DISCORD USERNAME>
Nikola123

src/scripts/generateTerrainMaps.ts

@@ -27,6 +27,7 @@ const maps = [
   "DeglaciatedAntarctica",
   "FalklandIslands",
   "Baikal",
+  "Halkidiki",
 ];
 
 const removeSmall = true;