Remove unused variables from kprop.c

Commit 29dee7d2cece615bec4616fa9b727e77210051db removed the
need for a ccache to hold the credentials used by the process,
but did not remove the ccname and ccache variables which became
unused as a result.
Make it easier to find ASN.1 codec functions

Expand out MAKE_CODEC macro invocations into MAKE_ENCODER and
MAKE_DECODER invocations, so that the defined function names appear in
the macro calls.  This makes it easier to find the function
definitions using grep, although one still has to look up the macro to
see what it does.
Remove length limit on PKINIT PKCS#12 prompt

Long pathnames can trigger the 128-byte prompt length limit in
pkinit_get_certs_pkcs12.  Use asprintf instead of snprintf.  Also
check the result of the prompter invocation.

ticket: 8011
target_version: 1.13.1
tags: pullup
Adjust asn1c test vector code for new asn1c

asn1c 0.9.22 added support for representing integers using unsigned
types if they have appropriate constraints.  This changes the
representation of RFC4120's UInt32 type from Integer_t to unsigned
long.  In make-vectors.c, this means we can use a static initializer
for kvno, and that the old method of calling asn_long2INTEGER doesn't
work.  Adjust make-vectors.c to assume the newer version of asn1c.
Add ASN.1 encoder and decoder for CAMMAC

Add internal type declarations for krb5_verifier_mac and krb5_cammac.
Add ASN.1 encoder and decoder functions and an internal free function
for krb5_cammac.  Add ASN.1 tests for krb5_cammac as well as asn1c
test vectors for Verifier and AD-CAMMAC.