feat: add gRPC reflection service (#431)

Co-authored-by: luofucong <luofucong@greptime.com>

src/api/build.rs

@@ -1,5 +1,9 @@
+use std::path::PathBuf;
+
 fn main() {
+    let default_out_dir = PathBuf::from(std::env::var("OUT_DIR").unwrap());
     tonic_build::configure()
+        .file_descriptor_set_path(default_out_dir.join("greptime_fd.bin"))
         .compile(
             &[
                 "greptime/v1/insert.proto",

src/api/src/v1.rs

@@ -1,6 +1,8 @@
 #![allow(clippy::derive_partial_eq_without_eq)]
 tonic::include_proto!("greptime.v1");
 
+pub const GREPTIME_FD_SET: &[u8] = tonic::include_file_descriptor_set!("greptime_fd");
+
 pub mod codec {
     tonic::include_proto!("greptime.v1.codec");
 }