Its because of this Fail to Install YnH 3.0 - #13 by djsets. I am unable to reproduce it as I don’t know which dependency is missing or there is problem in nodejs installation while peertube install scripts runs.
Issue on Peerube core app for this: PeerTube failing on YunoHost 3.0 on some VPS · Issue #830 · Chocobozzz/PeerTube · GitHub
As for @homerc he have different issue or maybe have two different issues. He is on Yunohost 3.x but still have Postgresql 9.4 running as seen in his logs. So he needs to remove Postgresql 9.4 and see if further installation goes well for him.