This is a late reply, but I am not encountering this same need and I've found a solution that works for us. I'm hoping this helps others who might find this thread.
While Moodle 3.3 will strip the iframe tags, it seems to not mind some other basic HTML tags, such as the <video> tag. I was able to successfully embed a video into a User Tour by using this tag. So you need to post your video to a publicly reachable location that will allow your video to be accessed and then you can use this code:
<video width="###" height="###" controls>
<source src="http://path/to/your/video.mp4" type="video/mp4" />
</video>
Replace the ## signs with the dimensions of your video.
More about how to use this tag can be found here:
https://www.w3schools.com/tags/tag_video.asp
I hope this helps someone!
