* Adds rekor TUF type

Co-authored-by: Santiago Torres <santiagotorres@purdue.edu>
Co-authored-by: Trishank Karthik Kuppusamy <trishank.kuppusamy@datadoghq.com>
Co-authored-by: Marina Moore <mnm678@gmail.com>
Signed-off-by: Asra Ali <asraa@google.com>

* add type documentation

Signed-off-by: Asra Ali <asraa@google.com>

* Address bob comments

Signed-off-by: Asra Ali <asraa@google.com>

* run make

Signed-off-by: Asra Ali <asraa@google.com>

* wip

Signed-off-by: Asra Ali <asraa@google.com>

* Address comments

Signed-off-by: Asra Ali <asraa@google.com>

Co-authored-by: Santiago Torres <santiagotorres@purdue.edu>
Co-authored-by: Trishank Karthik Kuppusamy <trishank.kuppusamy@datadoghq.com>
Co-authored-by: Marina Moore <mnm678@gmail.com>