Tag support color options

Created by: guqing

What this PR does?

标签支持设置颜色，颜色字段为非必填 默认值为 #cfd3d7, 为了返回值客户端统一默认颜色所以TagDTO的color字段默认值也为#cfd3d7

Why we need it?

#1559 (closed)