put model and app selector on the top of chat page

web/src/assets/css/chat-plus.styl

@@ -135,6 +135,34 @@ $borderColor = #4676d0;
         background-color: var(--el-bg-color)
         color var(--el-text-color-primary)
 
+        .chat-config {
+          height 30px
+          padding 10px 30px
+          display flex
+          justify-content center
+          justify-items center
+          border-bottom 1px solid #d9d9e3
+
+          .role-select-label {
+            color #ffffff
+          }
+
+          .el-select {
+            max-width 150px;
+            margin-right 10px;
+          }
+
+          .role-select {
+            max-width 130px;
+          }
+
+          .el-button {
+            .el-icon {
+              margin-right 5px;
+            }
+          }
+        }
+
         #container {
           overflow: hidden;
           width: 100%;