feat: lgbSelect 支持初始化 disabled 属性

src/admin/Bootstrap.Admin/wwwroot/lib/longbow-select/longbow-select.css

@@ -50,6 +50,10 @@
     cursor: not-allowed;
 }
 
+.form-select.is-disabled .form-select-append {
+    color: #c0c4cc;
+}
+
 .form-select-input {
     color: #606266;
     outline: none;

src/admin/Bootstrap.Admin/wwwroot/lib/longbow-select/longbow-select.js

@@ -119,6 +119,12 @@
             if (value !== undefined) attrs.push({ name: v, value: value });
         });
 
+        var disabled = this.$element.prop('disabled');
+        // set disabled property
+        if (disabled) {
+            this.disabled();
+        }
+
         // replace element select -> input hidden
         this.$element.remove();
         this.$element = $('<input type="hidden" data-toggle="lgbSelect" />').val(that.val()).insertBefore(this.$input);