Move watchdogd out of init

We're moving past a world where static executables are needed,
including watchdogd, so treat this like any other executable and place
it in /system/bin.

Bug: 73660730
Test: watchdogd still runs
Change-Id: I1f7508fd55dce6e9ee72a6ab7a085011a76c0053
diff --git a/watchdogd/Android.bp b/watchdogd/Android.bp
new file mode 100644
index 0000000..0fbc33c
--- /dev/null
+++ b/watchdogd/Android.bp
@@ -0,0 +1,14 @@
+cc_binary {
+    name: "watchdogd",
+    recovery_available: true,
+    srcs: ["watchdogd.cpp"],
+    cflags: [
+        "-Wall",
+        "-Wextra",
+        "-Werror",
+    ],
+    shared_libs: ["libbase"],
+    sanitize: {
+        misc_undefined: ["signed-integer-overflow"],
+    },
+}