Hey Sergey, thanks again for bringing that issue to my attention. I have some good news, I finally found the code I needed to get the add-ons to pre-install. It's not in the documentation yet, but I found it in a bug report while I was googling trying to fix the issue.
So, from now on you won't have to manually install anything, and, if you want to test it out, I added two more add-ons that I've found really helpful: BleuRaven's Blender for Unreal - tons of export options, and BlenderNPR's AbNormal - for editing normals to achieve better results with cel-shading and cartoon-style rendering.
Thanks, take care!