Support Touch ID on macOS

[timkgh]

Similar to #77

[yitsushi]

I'll put the same tags on it, but I don't think I can implement that feature as I have no way to test it, so unless someone with a mac (that supports Touch ID) pick this feature up, I don't see it'll be implemented in the near future (I don't plan to buy a macbook just to be able to implement this 🤣).

With the other one (#77), I have a few yubikey devices, but I had no time to even think how to approach it, but this one, well, described earlier.

[timkgh]

Looks like there is an age plugin, not sure how easy it is to wire them all together
https://github.com/remko/age-plugin-se

[yitsushi]

All contributions are welcome (I still can't test it) :)

[timkgh]

I haven't tried it, but I think this should just work with age-plugin-se because totp-cli can already accept the password on stdin 🎉 Simply store the password in an age encrypted file (that gets decrypted using age-plugin-se), just like the example in the README.