Title: #5450: kcm: add support for kerberos tgt renewals
I addressed several of the aforementioned issues, I'll make a second pass tomorrow. I
could not find any instances of `Mid-function variable declaration` but maybe I missed it
when looking over the changes.
Thanks again for the review and also for submitting a request to make the
marshalling/unmarshalling functions public!
See the full comment at https://github.com/SSSD/sssd/pull/5450#issuecomment-763153281