https://elest.io/open-source/jitsi
You can run it on local hosting or in the cloud using their deployments. It takes all of two clicks. Most important thing is to be hosting it either on arbitrary silicon or on your own hardware. I've used Jitsi for secure conversations and can recommend it "well enough".
Alternatively, if your project is smaller and you don't want to spring for a $12 a month rental price for an ec2, Signal also meets those requirements, and has some other additional niceties such as disappearing messages, secure payments, voice texting. However, since there is no anything being hosted by Signal since its peer to peer, you are limited to I think 4 people in a video call.