Add Deepin Desktop Environment

I wrote ebuilds for packages of Deepin Desktop Environment. Now dde can run, but there are issues. I could not handle them all. I upload the ebuilds before dealt with all the issues, and hope that dear friends can help me to test it and fix the problems. Thank you very much.
The known issues are:
1. the account, drivers and printer modules of deepin system settings did not work
2. the "share to weibo" function of deepin-screenshot did not work