fix every clippy warning possible, remove io_uring as default feature

this project's codebase is so horrendous, im shocked that no one has ran
clippy at all. it had ~200 total lint warnings, some with performance
issues and unsoundness, and the rest just very ugly codebase. i have sat
down and fixed as many of these as possible and i am exhausted.
i haven't fixed some extremely complex ones, but i brought it down from
~200 to ~30.

i have also removed io_uring as a default feature due to it falling
under the same category as linux eBPF: major kernel attack surface for
minimal performance gains. this also makes it impossible to cross-compile
from macOS to Linux because io_uring does not exist in Darwin land.
there are far better ways to achieve better performance than io_uring on
the codebase level.

Signed-off-by: strawberry <june@girlboss.ceo>

src/api/client_server/message.rs

@@ -128,7 +128,7 @@ pub async fn get_message_events_route(
     let to = body
         .to
         .as_ref()
-        .and_then(|t| PduCount::try_from_string(&t).ok());
+        .and_then(|t| PduCount::try_from_string(t).ok());
 
     services().rooms.lazy_loading.lazy_load_confirm_delivery(
         sender_user,