Add Netstratum link to users page

This update adds the Netstratum link to the users page as part of the CloudStack documentation and integration references. It ensures users can easily navigate to related Netstratum resources for infrastructure management and deployment support.

Author: vishnutasok333

src/pages/users.mdx

@@ -54,6 +54,7 @@ mailing list <b>users@cloudstack.apache.org</b>.
 - [Miriadis](http://www.miriadis.com)
 - [Neobitti](http://neobitti.fi)
 - [NetPoint](https://netpoint-dc.com/)
+- [Netstratum](https://netstratum.com/)
 - [NxtGen Cloud Technologies Private Limited](https://nxtgen.com)
 - [Openminds](http://www.openminds.be)
 - [Overweb srl](http://stacksquare.com)