kdc: Get KDC config out of CSR authorizer API

Part of refactoring to split out bx509/bnegotiate, add a kadmin REST service,
and move all of that out of kdc/.

kdc/simple_csr_authorizer.c

@@ -160,7 +160,7 @@ string_encode(const char *in)
 static KRB5_LIB_CALL krb5_error_code
 authorize(void *ctx,
           krb5_context context,
-          krb5_kdc_configuration *config,
+          const char *app,
           hx509_request csr,
           krb5_const_principal client,
           krb5_boolean *result)