add license/source code/language/platform for OPSI, remove duplicate entry, relate Client management and IT Asset Management

- https://download.uib.de/opsi_stable/doc/html/en/opsi-getting-started/opsi-getting-started.html
- https://www.opsi.org/documentation/opsi-license-and-copyright

README.md

@@ -127,12 +127,13 @@
 
 ## Client management
 
-*Managing software on desktop computers.*
+Managing software on desktop computers.
+
+_See also: [IT Asset Management](#it-asset-management)_
 
 * [Chocolatey](https://chocolatey.org/) – Windows CLI package manager written in .NET/PS, based on [NuGet](https://www.nuget.org/).
 * [just-install](https://just-install.github.io/) – Python script for downloading and silently installing MSI files.
 * [OCS Inventory NG](https://ocsinventory-ng.org/?lang=en) - Inventory, deployment and network scan.
-* [Opsi](http://www.opsi.org) (open PC server integration) - Client Management for Windows based on Debian.
 * [WAPT](https://dev.tranquil.it/wiki/WAPT_-_apt-get_pour_Windows/en) - Network-wide (un)installation, configuration and upgrades of Windows based software.
 * [WPKG](http://wpkg.org/) - Software deployment, upgrade and removal program for Windows.
 
@@ -374,7 +375,7 @@ _See also: [IT Asset Management]([Ralph](#it-asset-management))_
 
 * [GLPI](https://www.glpi-project.org/) - Information Resource-Manager with an additional Administration Interface.
 * [OCS Inventory NG](https://ocsinventory-ng.org/?lang=en) - Enables users to inventory their IT assets.
-* [OPSI](http://www.opsi.org) - Hardware and software inventory, deployment, and patching for Linux and Windows.
+* [OPSI](http://www.opsi.org) - Hardware and software inventory, client management, deployment, and patching for Linux and Windows. ([Source Code](https://github.com/opsi-org/)) `GPL-3.0/AGPL-3.0` `OVF/Python`
 * [RackTables](http://racktables.org/) - Datacenter and server room asset management like document hardware assets, network addresses, space in racks, networks configuration. ([Source Code](https://github.com/RackTables/racktables), [Demo](https://www.racktables.org/demo.php)) `GPL-2.0` `PHP`
 * [Ralph](https://ralph.allegro.tech/) - Asset management, DCIM and CMDB system for large Data Centers as well as smaller LAN networks. ([Source Code](https://github.com/allegro/ralph), [Demo](https://github.com/allegro/ralph#live-demo)) `Apache-2.0` `Python/Docker`
 * [Snipe IT](https://snipeitapp.com/) - Asset & license management software. ([Source Code](https://github.com/snipe/snipe-it)) `AGPL-3.0` `PHP`