Move stor commands to category Database (#11315)

Fixes #11309

crates/nu-protocol/src/signature.rs

@@ -46,6 +46,7 @@ pub enum Category {
     Conversions,
     Core,
     Custom(String),
+    Database,
     Date,
     Debug,
     Default,
@@ -78,6 +79,7 @@ impl std::fmt::Display for Category {
             Category::Conversions => "conversions",
             Category::Core => "core",
             Category::Custom(name) => name,
+            Category::Database => "database",
             Category::Date => "date",
             Category::Debug => "debug",
             Category::Default => "default",