No, it's not an official channel. This is basically just a copy of my YouTube channel (https://www.youtube.com/channel/UC2f7kCSzhtKGB56QhCoNe-A)
Since CIG is publishing so much material, it sometimes can be very difficult to find the stuff you are looking for, so that's why my channel is just focusing on the more technical part of Star Citizens development process.
I initially made this channel just for me, so i had an archive of reference materials in case i wanted to explain somebody how things work in SC. Then I could just link the appropriate video instead of having to explain everything.

PS:
I suggested to CIG to publish their stuff on here as well btw, but I don't think they are very interested. DTube has one major drawback right now, which is, that you have to host the videos yourself if you want to have them available for a long time. You don't have this problem on YouTube. Google will host the videos forever and also in 4k. That's what CIG needs, so i can understand, why they are not publishing here on DTube.