There are severall contribs that I think can be configured to allow https uploads to an ibay:
"Webshare"
https://wiki.contribs.org/Webshare"OpenUpload"
https://wiki.contribs.org/OpenUpload"SharedFolders"
https://wiki.contribs.org/SharedFolders"Pydio"
https://wiki.contribs.org/PydioThere are probably simpler PHP apps for simple file uploads, and many standard "web apps" - such as wordpress or drupal - also allow uploads.
Ultimately, I setup Owncloud/Nextcloud on a separate Ubuntu box as a general purpose Dropbox/Google Drive replacement - which lets me mount SME server folders as "external data" shares using either SMB or SFTP.
If you want to allow remote developers to sync website content with an i-bay, you might want to look at
UserManager,
Remoteuseraccess, per-user ssh keys, and creative user & ibay permissions, or give them VPN access and configure FTP to work for them over the VPN.
If you aren't supporting anyone else -- that is, if you're maintaining the server yourself, you can get to your ibays as 'root' using any
SFTP client.