Implement getBonusTime in Corporation

Used documentation from other 'getBonusTime' methods

src/ScriptEditor/NetscriptDefinitions.d.ts

@@ -6651,6 +6651,17 @@ export interface Corporation extends WarehouseAPI, OfficeAPI {
    *
    */
   sellShares(amount: number): void;
+  /**
+   * Get bonus time.
+   * 
+   * “Bonus time” is accumulated when the game is offline or if the game is inactive in the browser.
+   *
+   * “Bonus time” makes the game progress faster.
+   *
+   * @returns Bonus time for the Corporation mechanic in milliseconds.
+   */
+   getBonusTime(): number;
+  
 }
 
 /**