[Community] Launch sig GIS in openGauss Community

Hey team, GIS, as known as Geographic Information System. Super Map has launched a repository named Yukon about GIS in openGauss Community. https://gitee.com/opengauss/Yukon On the other hand, we need to launch a new sig to lead the direction of GIS. GIS SIG will develop and maintain the Geographic Information System of the openGauss community. The PR is submitted here: https://gitee.com/opengauss/tc/pulls/59 Welcome you guys to join sig GIS. Thanks very much. Best Regards, Edison Xiang