I am sure it has lot of missing elements. Lets skip the login/registration part for now and focus on the meat of the application which is send and receive calls, store vm on cloud, store meetings on cloud and video/audio conference calls. We can later try to do the admin/login feature. For saving to cloud and retrieving we can surely use web services. I have used firebase in the past for a simple hybrid app. You might want to take a look at that. Its pretty straight forward. IF thats not usable we can use either microsoft azure (I will investigate on pricing) or any other cloud service thats cheaper or even free :). For phone feature, I think webRTC is usable. I have not used it but you can investigate and see. WebRTC provides everything we want out of the box. Here are some features I was looking for in phase 1. If android and iphone hybrid app is too much work, I can live with responsive web application and see how it goes.
Ring Central is just a reference app to see what I am looking for. The idea is to replace desk phones and also any other app that is used for conference calls or meetings. The app should be a pure web based app that can replace your desk phones. No external equipment should be involved. The app should be accessible either from any device that the user wants to use (smartphone, laptop, etc) with valid AD credentials. The whole point of equipment installation will defeat the purpose of my project. I do have kind of a flow ready.
1. Phone calls (audio and video) and capability to send and receive VMs through cloud
2. Conference calls and capability to send and receive audio and video through cloud - includes being able to screen share.
3. Capability to be able to do presentation via phone call in case on 1:1 discussion about a topic. Kind of like screen share on lync messenger
4. If possible integrate with AD so that its secured. The VM retrievals should be secured as well. - this can be done at the end.