Enable library users to detect if a smart card doesn't support PIV (#476)

* Enable library users to detect if a smart card doesn't support PIV

Closes iqlusioninc/yubikey.rs#456.

* Avoid resetting the card if we fail to select PIV or fetch version/serial

src/piv.rs

@@ -73,6 +73,12 @@ use {
 #[cfg(feature = "untested")]
 use zeroize::Zeroizing;
 
+/// PIV Applet Name
+pub(crate) const APPLET_NAME: &str = "PIV";
+
+/// PIV Applet ID
+pub(crate) const APPLET_ID: &[u8] = &[0xa0, 0x00, 0x00, 0x03, 0x08];
+
 const CB_ECC_POINTP256: usize = 65;
 const CB_ECC_POINTP384: usize = 97;