feat: integrate serialization and string borrowing

This commit adds lifetimes to the diff and realdom methods so consumers may borrow the contents of the DOM for serialization or asynchronous modifications.

packages/core/src/util.rs

@@ -8,7 +8,7 @@ impl DebugDom {
         Self { counter: 0 }
     }
 }
-impl RealDom for DebugDom {
+impl<'a> RealDom<'a> for DebugDom {
     fn push_root(&mut self, root: RealDomNode) {}
 
     fn append_child(&mut self) {}