Migrate to hashbrown structures

src/main.rs

@@ -34,7 +34,7 @@ use iced_core::window::Position;
 use iced_core::window::settings::PlatformSpecific;
 use mimalloc::MiMalloc;
 use rusqlite::Connection;
-use std::collections::HashMap;
+use hashbrown::HashMap;
 
 #[global_allocator]
 static GLOBAL: MiMalloc = MiMalloc;