primary-site: document s3_compatible support (#88)

### Changelog
None. 
### Docs

This is already documented here:
https://docs.foxglove.dev/docs/primary-sites/self-hosting/installation#tag/Layouts/paths/~1layouts/get
but not in comments.

charts/primary-site/values.yaml

@@ -9,7 +9,7 @@ globals:
 
   foxgloveApiUrl: https://api.foxglove.dev
 
-  ## Supported storageProvider values are: `google_cloud`, `aws` or `azure`
+  ## Supported storageProvider values are: `google_cloud`, `aws`, `azure`, or `s3_compatible`.
   ## If `azure` is used, then the `@azure.storageAccountName` and `@azure.serviceUrl` values
   ## are required. If `aws` is used, then the `@aws.region` value is required.
   lake: