PortableApps’ XAMPP Launcher may be a good starting point, if they need full control of the server environment. If they just need full control over web content (and not server configuration), that should be possible with ACLs in a normal XAMPP installation.
SnipeIT. It’s free and open source.
https://snipeitapp.com
Netbox is also nice for managing your datacenter and switch closets. Again, free and open source: https://netbox.readthedocs.io/en/stable/