rpc: init wrapper crate + global: snapshot

crates/brk_iterator/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "brk_iterator"
+description = "A Bitcoin block iterator"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+homepage.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+build = "build.rs"
+
+[dependencies]
+bitcoin = { workspace = true }
+brk_reader = { workspace = true }
+brk_rpc = { workspace = true }