refactor(tools/rust-crates-advisory): move advisory-db to 3p

Change-Id: Iaaed35de078292c0c99a7c83de9ca5fdf27b8135
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3711
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>

third_party/rustsec-advisory-db/default.nix

@@ -0,0 +1,9 @@
+{ pkgs, ... }:
+
+pkgs.fetchFromGitHub {
+  owner = "RustSec";
+  repo = "advisory-db";
+  # TODO(Profpatsch): this will have to be updated regularly, how?
+  rev = "113188c62380753f01ff0df5edb7d67a300b143a";
+  sha256 = "0v086ybwr71zgs5nv8yr4w2w2d4daxx6in2s1sjb4m41q1r9p0wj";
+}