chore: reorganize rust crates

crates/libpk/src/util/mod.rs

@@ -0,0 +1 @@
+pub mod redis;

crates/libpk/src/util/redis.rs

@@ -0,0 +1,15 @@
+use fred::error::RedisError;
+
+pub trait RedisErrorExt<T> {
+    fn to_option_or_error(self) -> Result<Option<T>, RedisError>;
+}
+
+impl<T> RedisErrorExt<T> for Result<T, RedisError> {
+    fn to_option_or_error(self) -> Result<Option<T>, RedisError> {
+        match self {
+            Ok(v) => Ok(Some(v)),
+            Err(error) if error.is_not_found() => Ok(None),
+            Err(error) => Err(error),
+        }
+    }
+}