Add new initial_repositories configuration docs (#401)

docs/docs/explanations/advanced-custom-settings.md

@@ -113,6 +113,30 @@ jupyterhub:
       users: true
 ```
 
+### JupyterLab
+
+Nebari supports two main configuration options for JupyterLab:
+
+- `jupyterlab.idle_culler` - This is used to configure the idle culler for JupyterLab. See [idle culling](/docs/how-tos/idle-culling) for more information.
+
+```yaml
+jupyterlab:
+  idle_culler:
+    kernel_cull_idle_timeout: 30
+```
+
+- `jupyterlab.initial_repositories` - Clones specified repositories into user directories upon JupyterLab instance initialization. Accepts a list of `name: url` pairs, with each `name` becoming the folder name in the user's home directory.
+
+```yaml
+jupyterlab:
+  initial_repositories:
+    - examples/nebari-demo: https://github.com/nebari-dev/nebari-demo.git
+```
+
+:::note Note
+Currently only public git repositories are supported. Path location key should not start or end with trailing slash.
+:::
+
 ### Terraform
 
 The Nebari configuration file provides a huge number of configuration options for customizing your Nebari infrastructure. While these options are sufficient for an average user, they
@@ -143,7 +167,7 @@ This is quite useful for pinning the IP Address of the load balancer.
 
 <TabItem value="azure" label="Azure" default="true" >
 
-You can deploy your cluster into a Virtual Private Network (VPN) or Virtual Network (VNET). 
+You can deploy your cluster into a Virtual Private Network (VPN) or Virtual Network (VNET).
 
 An example configuration for Azure is given below:
 
@@ -165,13 +189,12 @@ azure:
   vnet_subnet_id: '/subscriptions/<subscription_id>/resourceGroups/<resource_group>/providers/Microsoft.Network/virtualNetworks/<vnet-name>/subnets/<subnet-name>'
   network_profile:
     service_cidr: "10.0.2.0/24" # how many IPs would you like to reserve for Nebari
-    network_plugin: "azure" 
+    network_plugin: "azure"
     network_policy: "azure"
     dns_service_ip: "10.0.2.10" # must be within the `service_cidr` range from above
-    docker_bridge_cidr: "172.17.0.1/16" # no real need to change this 
-
-```
+    docker_bridge_cidr: "172.17.0.1/16" # no real need to change this
 
+```
 
 </TabItem>