Convert Blockstore Rewards cf to protobuf (#12860)

* Add Blockstore protobuf cf type

* Add Rewards message to proto and make generated pub

* Convert Rewards cf to ProtobufColumn

* Add bench

* Adjust tags

* Move solana proto definitions and conversion methods to new crate

storage-proto/build-proto/src/main.rs

@@ -0,0 +1,16 @@
+fn main() -> Result<(), std::io::Error> {
+    let manifest_dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+
+    let out_dir = manifest_dir.join("../proto");
+    let proto_files = manifest_dir.join("../src");
+
+    println!("Protobuf directory: {}", proto_files.display());
+    println!("output directory: {}", out_dir.display());
+
+    tonic_build::configure()
+        .build_client(true)
+        .build_server(false)
+        .format(true)
+        .out_dir(&out_dir)
+        .compile(&[proto_files.join("confirmed_block.proto")], &[proto_files])
+}