Added Application Insights Docs (#909)

* added app insights docs

* Update docs/appinsights/appinsights.md

Co-Authored-By: Janani Vasudevan <49576785+jananivMS@users.noreply.github.com>

* added secrets section

* Update docs/appinsights/appinsights.md

Co-Authored-By: Janani Vasudevan <49576785+jananivMS@users.noreply.github.com>

Co-authored-by: William Mortl <32373900+WilliamMortlMicrosoft@users.noreply.github.com>
Co-authored-by: Janani Vasudevan <49576785+jananivMS@users.noreply.github.com>

docs/appinsights/appinsights.md

@@ -0,0 +1,25 @@
+# App Insights Operator
+
+This operator deploys an Application Insights instance into a specified resource group at the specified location.
+
+Learn more about Application Insights [here](https://docs.microsoft.com/en-us/azure/azure-monitor/app/app-insights-overview).
+
+Here is a [sample YAML](/config/samples/azure_v1alpha1_appinsights.yaml) to provision an Application Insights instance.
+
+### Required Fields
+
+An Application Insights instance needs the following fields to deploy, along with a location and resource group.
+
+* `Kind` specify the kind of application this component refers to, possible values are: 'web', 'ios', 'other', 'store', 'java', 'phone'
+* `ApplicationType` specify the types of application being monitored, possible values are: 'web', 'other'
+
+### Secrets
+
+After creating an Application Insights instance, the operator stores a JSON formatted secret with the following fields. This secret is stored as a Kubernetes Secret or in an Azure Keyvault, with the same name as your Application Insights instance.
+For more details on where the secrets are stored, look [here](/docs/secrets.md)
+
+* `instrumentationKey`
+
+## Deploy, view and delete resources
+
+You can follow the steps [here](/docs/customresource.md) to deploy, view and delete resources.