增加了一个超链聊天跳转

在“运营设置里面”增加了“聊天页面2链接”，方便将项目（https://github.com/Dooy/chatgpt-web-midjourney-proxy） 替换掉原来的AMA问天。

Changes to be committed:
    modified:   common/constants.go
    modified:   controller/misc.go
    modified:   model/option.go
    modified:   web/src/App.js
    modified:   web/src/components/OperationSetting.js
    modified:   web/src/components/TokensTable.js

model/option.go

@@ -76,6 +76,7 @@ func InitOptionMap() {
 	common.OptionMap["GroupRatio"] = common.GroupRatio2JSONString()
 	common.OptionMap["TopUpLink"] = common.TopUpLink
 	common.OptionMap["ChatLink"] = common.ChatLink
+	common.OptionMap["ChatLink2"] = common.ChatLink2
 	common.OptionMap["QuotaPerUnit"] = strconv.FormatFloat(common.QuotaPerUnit, 'f', -1, 64)
 	common.OptionMap["RetryTimes"] = strconv.Itoa(common.RetryTimes)
 	common.OptionMap["DataExportInterval"] = strconv.Itoa(common.DataExportInterval)
@@ -241,6 +242,8 @@ func updateOptionMap(key string, value string) (err error) {
 		common.TopUpLink = value
 	case "ChatLink":
 		common.ChatLink = value
+	case "ChatLink2":
+		common.ChatLink2 = value
 	case "ChannelDisableThreshold":
 		common.ChannelDisableThreshold, _ = strconv.ParseFloat(value, 64)
 	case "QuotaPerUnit":