Add ONVIF bicep files (#117)

## Purpose
<!-- Describe the intention of the changes being proposed. What problem
does it solve or functionality does it add? -->
* Add ONVIF bicep files to support how-to article:
https://learn.microsoft.com/en-us/azure/iot-operations/discover-manage-assets/howto-use-onvif-connector

## Does this introduce a breaking change?
<!-- Mark one with an "x". -->
```
[ ] Yes
[x] No
```

## Pull Request Type
What kind of change does this Pull Request introduce?

<!-- Please check the one that applies to this PR using "x". -->
```
[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[x] Documentation content changes
[ ] Other... Please describe:
```

Author: dominicbetts

samples/media-connector-bicep/aep-media-connector.bicep

@@ -9,7 +9,7 @@ param customLocationName string
 @description('Specifies the name of the asset endpoint resource to create.')
 param aepName string
 
-@description('The name of the Kubernetes secret you are using.')
+@description('The name of the Kubernetes secret you are using to store the camera credentials.')
 param secretName string
 
 /*****************************************************************************/

samples/onvif-connector-bicep/aep-onvif-connector.bicep

@@ -0,0 +1,38 @@
+metadata description = 'Asset endpoint profile for ONVIF connector'
+
+@description('The ONVIF discovery endpoint.')
+param onvifAddress string
+
+@description('The name of the custom location you are using.')
+param customLocationName string
+
+@description('Specifies the name of the asset endpoint resource to create.')
+param aepName string
+
+@description('The name of the Kubernetes secret you are using to store the camera credentials.')
+param secretName string
+
+/*****************************************************************************/
+/*                          Asset endpoint profile                           */
+/*****************************************************************************/
+resource assetEndpoint 'Microsoft.DeviceRegistry/assetEndpointProfiles@2024-11-01' = {
+  name: aepName
+  location: resourceGroup().location
+  extendedLocation: {
+    type: 'CustomLocation'
+    name: customLocationName
+  }
+  properties: {
+    targetAddress: onvifAddress
+    endpointProfileType: 'Microsoft.Onvif'
+    #disable-next-line no-hardcoded-env-urls //Schema required during public preview
+    additionalConfiguration: '{"@schema":"https://aiobrokers.blob.core.windows.net/aio-onvif-connector/1.0.0.json"}'
+    authentication: {
+      method: 'UsernamePassword'
+      usernamePasswordCredentials: {
+        passwordSecretName: '${secretName}/password'
+        usernameSecretName: '${secretName}/username'
+      }
+    }
+  }
+}

samples/onvif-connector-bicep/asset-ptz.bicep

@@ -0,0 +1,21 @@
+metadata description = 'ONVIF camera PTZ capabilities'
+param aepName  string
+param customLocationName string
+param assetName     string = 'camera-ptz'
+param displayName string = 'Camera PTZ service'
+
+/*****************************************************************************/
+/*                                    Asset                                  */
+/*****************************************************************************/
+resource asset 'Microsoft.DeviceRegistry/assets@2024-11-01' = {
+  name: assetName
+  location: resourceGroup().location
+  extendedLocation: {
+    type: 'CustomLocation'
+    name: customLocationName
+  }
+  properties: {
+    displayName: displayName
+    assetEndpointProfileRef: aepName
+  }
+}