feat: namespaced attributes

this commit adds namespaced attributes. This lets us support attribute groups, and thus, inline styles.

This namespaced attribute stuff is only available for styles at the moment, though it theoretically could be enabled for any other attributes.

packages/core/src/nodes.rs

@@ -216,6 +216,11 @@ pub struct VElement<'a> {
 pub struct Attribute<'a> {
     pub name: &'static str,
     pub value: &'a str,
+
+    /// If an attribute is "namespaced", then it belongs to a group
+    /// The most common namespace is the "style" namespace
+    // pub is_dynamic: bool,
+    pub namespace: Option<&'static str>,
 }
 
 impl<'a> Attribute<'a> {