Improve docs for importing a realm in a container

docs/guides/src/main/server/containers.adoc

@@ -155,6 +155,19 @@ Keycloak only allows to create the initial admin user from a local network conne
 -e KEYCLOAK_ADMIN_PASSWORD=change_me
 ----
 
+== Importing A Realm On Startup
+
+The https://quay.io/keycloak/keycloak[published Keycloak containers] have a directory `/opt/keycloak/data/import`. If you put one or more import files in that directory via a volume mount or other means and add the startup argument `--import-realm`, the Keycloak container will import that data on startup! This may only make sense to do in Dev mode.
+
+[source, bash]
+----
+podman|docker run --name keycloak_unoptimized -p 8080:8080 \
+        -e KEYCLOAK_ADMIN=admin -e KEYCLOAK_ADMIN_PASSWORD=change_me \
+        -v /path/to/realm/data:/opt/keycloak/data/import
+        quay.io/keycloak/keycloak:latest \
+        start-dev --import-realm
+----
+
 Feel free to join the open https://github.com/keycloak/keycloak/discussions/8549[GitHub Discussion] around enhancements of the admin bootstrapping process.
 
 </@tmpl.guide>

docs/guides/src/main/server/importExport.adoc

@@ -82,6 +82,8 @@ You are also able to import realms when the server is starting by using the `--i
 When you set the `--import-realm` option, the server is going to try to import any realm configuration file from the `data/import` directory. Each file in this directory should
 contain a single realm configuration. Only regular files using the `.json` extension are read from this directory, sub-directories are ignored.
 
+NOTE: For the https://quay.io/keycloak/keycloak[published containers], the import directory is `/opt/keycloak/data/import`
+
 If a realm already exists in the server, the import operation is skipped.
 
 === Using Environment Variables within the Realm Configuration Files