A “supported installation” is one that follows the INSTALL-cloud.md instructions. Discourse requires a whole bunch of packages of certain versions. It’s quite possible to install those things yourself, but if you do, and it doesn’t work, then you’re on your own. People here won’t help you.
Things like hostgator won’t work. You need full root access to your own (probably virtual) machine. You don’t get that with services like hostgator and tools like cpanel.
It might be possible to deploy Discourse on Heroku, but I install Discourse for a living and wasn’t able to figure out how to make Heroku work in 10 minutes. It’s likely that’s because I don’t understand how Heroku works, but if you want things to work easily, go with something like Digital Ocean.
See also:
https://meta.discourse.org/t/using-heroku-docker/43048?u=pfaffman