feat(xatu): scaffold source collection

src/xatu/BUILD

@@ -0,0 +1,18 @@
+load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_library")
+
+rust_library(
+    name = "xatu_lib",
+    crate_name = "xatu",
+    srcs = ["xatu.rs"],
+)
+
+rust_binary(
+    name = "xatu",
+    crate_name = "xatu_cli",
+    srcs = ["xatu_main.rs"],
+    deps = [
+        ":xatu_lib",
+        "//src/monorepo:monorepo",
+        "//third_party/crates:clap",
+    ],
+)