misc/libtatsu: Import libtatsu-1.0.5

Library handling the communication with Apple's Tatsu Signing Server (TSS).

This library is part of the libimobiledevice project. The main purpose of
this library is to allow creating TSS request payloads, sending them to
Apple's TSS server, and retrieving and processing the response.

The code was originally part of idevicerestore and has been split out to
its own library, while obviously idevicerestore will remain the main
consumer.
