Clean up yk8 branch

[timweri]

Note: The large diff is due to the inclusion of Cargo.lock.

Followed #27 and implemented our own type which implements KeyType, allowing us to avoid importing p256 and p384. However, I used spki for signature verification instead of ring.

These tests work on:

• Firmware 5.7.1 with default 3DES management keys:
• Firmware 5.7.2 with default AES192 management keys:

cargo run --example yk-provision --features yubikey-support -- \
  --slot R3 --subject "my-test-key" --type p384

cargo run --example yk-provision --features yubikey-support -- \
  --slot R3 --subject "my-test-key" --type p256

cargo run --example yk-generate-csr --features yubikey-support -- -s R3

Management key parsing

When we parse management key, we need to now know the algorithm. So calls like unlock now needs to also query the Yubikey for the algorithm before parsing the management key.