Add some docs

Author: sbernauer

docs/modules/hive/pages/usage-guide/derby-example.adoc

@@ -9,7 +9,6 @@ It should generally be safe to simply use the latest image version that is avail
 .Create a single node Apache Hive Metastore cluster using Derby:
 [source,yaml]
 ----
----
 apiVersion: hive.stackable.tech/v1alpha1
 kind: HiveCluster
 metadata:
@@ -52,7 +51,6 @@ Then, connect to localhost:9001 and login with the user `minio-access-key` and p
 Deploy the hive cluster:
 [source,yaml]
 ----
----
 apiVersion: hive.stackable.tech/v1alpha1
 kind: HiveCluster
 metadata:

rust/operator-binary/src/crd/mod.rs

@@ -526,6 +526,7 @@ impl MetadataDatabaseConnection {
         }
     }
 
+    /// Name of the database as it should be passed using the `--db-type` CLI argument to Hive
     pub fn as_hive_db_type(&self) -> &str {
         match self {
             MetadataDatabaseConnection::Postgresql(_) => "postgres",