feat: Add slowmode functionality to text channels (#680)

* feat: Add slowmode functionality to text channels

Signed-off-by: arsabutispik <ispik@ispik.dev>

* fix: use atomic check-and-set to prevent spamming with scripts

Signed-off-by: arsabutispik <ispik@ispik.dev>

* feat: Add BypassSlowmode permission to channel permissions

Signed-off-by: arsabutispik <ispik@ispik.dev>

* refactor: Use set_options instead of manually building the command

Signed-off-by: arsabutispik <ispik@ispik.dev>

---------

Signed-off-by: arsabutispik <ispik@ispik.dev>

crates/core/result/src/rocket.rs

@@ -42,6 +42,9 @@ impl<'r> Responder<'r, 'static> for Error {
             ErrorType::NotInGroup => Status::NotFound,
             ErrorType::AlreadyPinned => Status::BadRequest,
             ErrorType::NotPinned => Status::BadRequest,
+            ErrorType::InSlowmode {
+                retry_after: _,
+            } => Status::TooManyRequests,
             ErrorType::InvalidFlagValue => Status::BadRequest,
 
             ErrorType::CantCreateServers => Status::Forbidden,