feat(provider): add MiniMax (#6318)

* feat(provider): add MiniMax

* feat(provider): reintroduce MiniMax provider configuration and remove deprecated source

---------

Co-authored-by: Soulter <905617992@qq.com>

astrbot/core/config/default.py

@@ -1132,6 +1132,18 @@ CONFIG_METADATA_2 = {
                         "proxy": "",
                         "custom_headers": {},
                     },
+                    "MiniMax": {
+                        "id": "minimax",
+                        "provider": "minimax",
+                        "type": "openai_chat_completion",
+                        "provider_type": "chat_completion",
+                        "enable": True,
+                        "key": [],
+                        "api_base": "https://api.minimaxi.com/v1",
+                        "timeout": 120,
+                        "proxy": "",
+                        "custom_headers": {},
+                    },
                     "xAI": {
                         "id": "xai",
                         "provider": "xai",