Yes, it can be done via the mssadmin account. Just upload the content to the /var/www/html/mss/custom folder.

Any other user can host their content by putting the content in /home/username/public_html.

The former can be accessed via https://server/ and the later via https://server/~username/ from a browser on any system connected on the LAN.

For detailed step-by-step instructions, refer to the Content Platform section in the user manual. Familiarity with web server administration concepts is recommended to be able to fully exploit this feature.