add toolbar related logic

copied from chrome

Signed-off-by: kernelkind <kernelkind@gmail.com>

crates/notedeck_columns/src/lib.rs

@@ -27,6 +27,7 @@ mod subscriptions;
 mod support;
 mod test_data;
 pub mod timeline;
+mod toolbar;
 pub mod ui;
 mod unknowns;
 mod view_state;