Rewrite translated code to use the pcsc crate

This commit contains a "big bang" refactor/rewrite which does the
following:

- Replaces all `SCard*` FFI calls with the `pcsc` crate, which provides
  a safe, portable PC/SC API across Windows, macOS, and Linux
- Refactors the `util` module into modules representing the various
  device functions and concepts, e.g. `certificate`, `key`, `mgm`
- Replaces all usage of `libc` with `std` functionality, and in many
  places rewriting functionality to use safe code.
- Removes `ykpiv_` from all function names, and `Piv*` from type names.

In 20/20 hindsight I wish I had done this commit more incrementally so
as to make it easier to review. Que sera sera.

However, realistically we need to test all functionality on the device
to ensure that it actually works. Going forward I would like to put
pretty much all of the current code behind an `untested` cargo feature,
and then remove it for each bit of functionality we test.

src/apdu.rs

@@ -1,20 +1,18 @@
 //! Application Protocol Data Unit (APDU)
 
+use crate::{error::Error, response::Response, transaction::Transaction, Buffer};
 use std::fmt::{self, Debug};
 use zeroize::{Zeroize, Zeroizing};
 
 /// Size of a serialized APDU (5 byte header + 255 bytes data)
 pub const APDU_SIZE: usize = 260;
 
-/// Buffer type (self-zeroizing byte vector)
-pub(crate) type Buffer = Zeroizing<Vec<u8>>;
-
 /// Application Protocol Data Unit (APDU).
 ///
 /// These messages are packets used to communicate with the YubiKey using the
 /// Chip Card Interface Device (CCID) protocol.
 #[derive(Clone)]
-pub struct APDU {
+pub(crate) struct APDU {
     /// Instruction class - indicates the type of command, e.g. interindustry or proprietary
     cla: u8,
 
@@ -81,6 +79,12 @@ impl APDU {
         self
     }
 
+    /// Transmit this APDU using the given card transaction
+    pub fn transmit(&self, txn: &Transaction<'_>, recv_len: usize) -> Result<Response, Error> {
+        let response_bytes = txn.transmit(&self.to_bytes(), recv_len)?;
+        Ok(Response::from_bytes(response_bytes))
+    }
+
     /// Consume this APDU and return a self-zeroizing buffer
     pub fn to_bytes(&self) -> Buffer {
         let mut bytes = Vec::with_capacity(APDU_SIZE);