Simply implement achievement system and add achievement command (#2068)

* Implement achievement system

* Update src/main/java/emu/grasscutter/command/commands/AchievementCommand.java

Co-authored-by: Der Chien <b03902015@ntu.edu.tw>

* fix: redundant codes

* fix: redundant codes

* Update language files

---------

Co-authored-by: Der Chien <b03902015@ntu.edu.tw>

src/main/resources/languages/it-IT.json

@@ -124,6 +124,21 @@
       "no_account": "Account non trovato.",
       "description": "Modifica account utente"
     },
+    "achievement": {
+      "success": {
+        "grant": "🇺🇸Granted the achievement to %s.",
+        "revoke": "🇺🇸Revoked the achievement from %s.",
+        "progress": "🇺🇸Set progress of %s's achievement(id: %s) to %s.",
+        "grantall": "🇺🇸Granted %s achievement(s) to %s.",
+        "revokeall": "🇺🇸Revoked %s achievement(s) from %s."
+      },
+      "fail": {
+        "achievement_not_found": "🇺🇸Achievement not found.",
+        "already_achieved": "🇺🇸%s has already achieved the achievement.",
+        "not_yet_achieved": "🇺🇸%s hasn't achieved the achievement yet."
+      },
+      "description": "🇺🇸Grant, Revoke or Progress achievements."
+    },
     "announce": {
       "send_success": "Invia un annuncio con successo, puoi revocarlo /a revoca %s.",
       "refresh_success": "Aggiorna il file di configurazione dell'annuncio con successo. [Totale %s]",