refactor: Restructure project layout and clean up dependencies (#30)

This commit introduces a significant reorganization of the project structure to improve maintainability and clarity.

Key changes include:
- Adjusted the directory layout for a more logical module organization.
- Removed unused crate dependencies, reducing the overall project size and potentially speeding up build times.
- Updated import paths and configuration files to reflect the structural changes.

crates/s3select-api/src/query/function.rs

@@ -0,0 +1,38 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::sync::Arc;
+
+use datafusion::logical_expr::{AggregateUDF, ScalarUDF, WindowUDF};
+
+use crate::QueryResult;
+
+pub type FuncMetaManagerRef = Arc<dyn FunctionMetadataManager + Send + Sync>;
+pub trait FunctionMetadataManager {
+    fn register_udf(&mut self, udf: Arc<ScalarUDF>) -> QueryResult<()>;
+
+    fn register_udaf(&mut self, udaf: Arc<AggregateUDF>) -> QueryResult<()>;
+
+    fn register_udwf(&mut self, udwf: Arc<WindowUDF>) -> QueryResult<()>;
+
+    fn udf(&self, name: &str) -> QueryResult<Arc<ScalarUDF>>;
+
+    fn udaf(&self, name: &str) -> QueryResult<Arc<AggregateUDF>>;
+
+    fn udwf(&self, name: &str) -> QueryResult<Arc<WindowUDF>>;
+
+    fn udfs(&self) -> Vec<String>;
+    fn udafs(&self) -> Vec<String>;
+    fn udwfs(&self) -> Vec<String>;
+}