kdc: preserve value types in auditing

Preserve integer/boolean audit values as their native types; convert to strings
when logging only. This commit goes some way towards unifying the two auditing
APIs.

kdc/version-script.map

@@ -21,6 +21,8 @@ HEIMDAL_KDC_1.0 {
 		krb5_kdc_update_time;
 		krb5_kdc_pk_initialize;
 		_kdc_audit_addkv;
+		_kdc_audit_addkv_bool;
+		_kdc_audit_addkv_number;
 		_kdc_audit_addkv_object;
 		_kdc_audit_delkv;
 		_kdc_audit_getkv;