Cleanup nations (Part 3) 🧹 Remove nation strength (#2649)

## Description:

This PR removes the nation strength. Reasoning:

- It is currently unused. The backstory can be found in #2498
- It forces map-makers to do balancing work, which is probably not a
good idea
- It increases map-making work
- It increases nation balancing complexity by a lot (we need to have all
the json files in mind)
- It makes humans avoid map areas completely because there is always
that one, same, strong nation
- The map lead Nikola123 wants to "not deal with the stupid nations and
their balancing"

If the goal of nation strength was to make them feel different I would
suggest a nation personality system. Nations that love to boat, love to
ally, love to nuke, love to fullsend, etc.

Link to a discord discussion about nation strength:


https://discord.com/channels/1359946986937258015/1360078040222142564/1450973197251117218

## 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:

FloPinguin

src/core/GameRunner.ts

@@ -61,13 +61,7 @@ export async function createGameRunner(
         (n) =>
           new Nation(
             new Cell(n.coordinates[0], n.coordinates[1]),
-            new PlayerInfo(
-              n.name,
-              PlayerType.Nation,
-              null,
-              random.nextID(),
-              n.strength,
-            ),
+            new PlayerInfo(n.name, PlayerType.Nation, null, random.nextID()),
           ),
       );
 

src/core/configuration/Config.ts

@@ -94,7 +94,6 @@ export interface Config {
   userSettings(): UserSettings;
   playerTeams(): TeamCountConfig;
 
-  useNationStrengthForStartManpower(): boolean;
   startManpower(playerInfo: PlayerInfo): number;
   troopIncreaseRate(player: Player | PlayerView): number;
   goldAdditionRate(player: Player | PlayerView): Gold;

src/core/configuration/DefaultConfig.ts

@@ -802,31 +802,20 @@ export class DefaultConfig implements Config {
     }
   }
 
-  useNationStrengthForStartManpower(): boolean {
-    // Currently disabled: Nations became harder to play against due to AI improvements
-    // nation strength multiplier was unintentionally disabled during those AI improvements (playerInfo.nation was undefined),
-    // Re-enabling this without rebalancing Nation difficulty elsewhere may make them overpowered
-    return false;
-  }
-
   startManpower(playerInfo: PlayerInfo): number {
     if (playerInfo.playerType === PlayerType.Bot) {
       return 10_000;
     }
     if (playerInfo.playerType === PlayerType.Nation) {
-      const strength = this.useNationStrengthForStartManpower()
-        ? (playerInfo.nationStrength ?? 1)
-        : 1;
-
       switch (this._gameConfig.difficulty) {
         case Difficulty.Easy:
-          return 18_750 * strength;
+          return 18_750;
         case Difficulty.Medium:
-          return 25_000 * strength; // Like humans
+          return 25_000; // Like humans
         case Difficulty.Hard:
-          return 31_250 * strength;
+          return 31_250;
         case Difficulty.Impossible:
-          return 37_500 * strength;
+          return 37_500;
         default:
           assertNever(this._gameConfig.difficulty);
       }

src/core/game/Game.ts

@@ -418,7 +418,6 @@ export class PlayerInfo {
     public readonly clientID: ClientID | null,
     // TODO: make player id the small id
     public readonly id: PlayerID,
-    public readonly nationStrength?: number,
   ) {
     this.clan = getClanTag(name);
   }

src/core/game/TerrainMapLoader.ts

@@ -28,7 +28,6 @@ export interface Nation {
   coordinates: [number, number];
   flag: string;
   name: string;
-  strength: number;
 }
 
 export async function loadTerrainMap(