Create a tcti-transcript module

[AndreasFuchsTPM]

Create a tcti module that tracks a transcript of executed commands into a callback provided by the application.
Additionally, we could also support a bytebuffer and/or a file.

The intention is to get audit-sessions supported nicely and maybe also get some duplicate code out of tpm2-tools.

[joholl]

We can do that, but it should be "read-only", i.e. it cannot alter the commands/responses sent. Otherwise you just have another way to create new tctis.

[AndreasFuchsTPM]

Agreed