Stop using krb5_typed_data structure type

Stop using krb5_typed_data structure type

Use the krb5_pa_data structure type when encoding or decoding
TYPED-DATA.  Leave the krb5_typed_data structure definition in krb5.h
with a comment saying not to use it.  Remove krb5_free_typed_data
(which was never declared in krb5.h).  Remove some vestigial accessor
stuff related to PKINIT encoding and decoding TYPED-DATA, which was
unneeded since r25483.  Bump the accessor structure version to 19
accordingly.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@25601 dc483132-0cff-0310-8789-dd5450dbe970