Yes, it's possible to do via the Studio->Storage app. Go to the Files area there, upload the video file, for example with the mp4 extension.  After uploading you will get the record where the URL field will have the value like [your UNA's site URL]s/sys_files/t5ienvf7nejeggbsjqrxgk2fhfvpsrqe.mp4. Copy it and paste into the code like from this example https://www.w3schools.com/howto/howto_css_fullscreen_video.asp . Just replace there the src in this line to your own value:

<source src="rain.mp4" type="video/mp4">