rpc: init wrapper crate + global: snapshot

crates/brk_iterator/src/lib.rs

@@ -0,0 +1,13 @@
+use brk_rpc::Client;
+
+pub struct BlockIterator {
+    client: Client,
+}
+
+impl BlockIterator {
+    pub fn new(client: Client) -> Self {
+        Self { client }
+    }
+
+    pub fn iter() {}
+}