implement a tcti-rm

[AndreasFuchsTPM]

Idea would be to implement a Tcti that does the ContextSave/Load for the application. No arbitration between different context, just lifting the limit of max loaded object. Useful for /dev/tpm0 and tbs

[joholl]

Nice idea, who would have thought, how great the tcti thing would be!

We might also want the option to specify state file path where contexts are saved (as a single file). This raises the question if we want to think of a common configuration syntax (including a common configuration parser). Because this is it's own topic, I will open another issue, see #2659 .