feat: Introduce settings package and refactor constants

- Added a new `setting` package to replace the `constant` package for configuration management, improving code organization and clarity.
- Moved various configuration variables such as `ServerAddress`, `PayAddress`, and `SensitiveWords` to the new `setting` package.
- Updated references throughout the codebase to use the new `setting` package, ensuring consistent access to configuration values.
- Introduced new files for managing chat settings and midjourney settings, enhancing modularity and maintainability of the code.

model/token.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 	"gorm.io/gorm"
 	"one-api/common"
-	"one-api/constant"
 	relaycommon "one-api/relay/common"
+	"one-api/setting"
 	"strconv"
 	"strings"
 )
@@ -325,7 +325,7 @@ func PostConsumeTokenQuota(relayInfo *relaycommon.RelayInfo, userQuota int, quot
 						prompt = "您的额度已用尽"
 					}
 					if email != "" {
-						topUpLink := fmt.Sprintf("%s/topup", constant.ServerAddress)
+						topUpLink := fmt.Sprintf("%s/topup", setting.ServerAddress)
 						err = common.SendEmail(prompt, email,
 							fmt.Sprintf("%s，当前剩余额度为 %d，为了不影响您的使用，请及时充值。<br/>充值链接：<a href='%s'>%s</a>", prompt, userQuota, topUpLink, topUpLink))
 						if err != nil {