Build wheels using setuptools-rust

Build wheels in a more "standard" way using setuptools-rust, which makes
our life easier when dealing with multiple different platforms.

Also use the new bdk-ffi's `generate` binary instead of relying on
uniffi's bindgen cli.

nix/uniffi_bindgen.nix

@@ -0,0 +1,20 @@
+with import <nixpkgs> {};
+
+rustPlatform.buildRustPackage rec {
+  pname = "uniffi_bindgen";
+  version = "0.15.2";
+  src = fetchFromGitHub {
+    owner = "mozilla";
+    repo = "uniffi-rs";
+    rev = "6fa9c06a394b4e9b219fa30fc94e353d17f86e11";
+    # rev = "refs/tags/v0.14.1";
+    sha256 = "1chahy1ac1r88drpslln2p1b04cbg79ylpxzyyp92s1z7ldm5ddb"; # 0.15.2
+    # sha256 = "1mff3f3fqqzqx1yv70ff1yzdnvbd90vg2r477mzzcgisg1wfpwi0"; # 0.14.1
+    fetchSubmodules = true;
+  } + "/uniffi_bindgen/";
+
+  doCheck = false;
+  cargoSha256 = "sha256:08gg285fq8i32nf9kd8s0nn0niacd7sg8krv818nx41i18sm2cf3"; # 0.15.2
+  # cargoSha256 = "sha256:01zp3rwlni988h02dqhkhzhwccs7bhwc1alhbf6gbw3av4b0m9cf"; # 0.14.1
+  cargoPatches = [ ./uniffi_0.15.2_cargo_lock.patch ];
+}