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.

.gitignore

@@ -5,3 +5,8 @@ __pycache__/
 libbdkffi.dylib
 .idea/
 .DS_Store
+
+*.swp
+
+src/bdkpython/bdk.py
+*.whl