feat(core): implement message tasks

includes:
- acknowledgements
- last_message_id
- embeds
- web push

crates/core/database/src/lib.rs

@@ -81,6 +81,7 @@ pub mod util;
 pub use models::*;
 
 pub mod events;
+pub mod tasks;
 
 /// Utility function to check if a boolean value is false
 pub fn if_false(t: &bool) -> bool {