Add content for istio (#1487)

* Add content for istio

* Update content/roadmaps/102-devops/content/105-infrastructure-as-code/100-service-mesh/101-istio.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/102-devops/content/105-infrastructure-as-code/100-service-mesh/101-istio.md

@@ -1 +1,6 @@
-# Istio
+# Istio
+
+Istio is an open source service mesh platform that provides a way to control how microservices share data with one another. It includes APIs that let Istio integrate into any logging platform, telemetry, or policy system. Istio is designed to run in a variety of environments: on-premise, cloud-hosted, in Kubernetes containers, in services running on virtual machines, and more.
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+<BadgeLink colorScheme='red' badgeText='Read' href='https://www.redhat.com/en/topics/microservices/what-is-istio'>What is Istio?</BadgeLink>