Define handles as key identifiers

Define psa_key_handle_t to be equal to
mbedtls_svc_key_id_t. Make the handle of a persistent
key be equal to its key identifier. For volatile keys,
make the key handle equal to the volatile key
identifier of the created volatile key.

The unit tests are modified just to make them compile
not to make them run successfully. They are fixed in
the subsequent commits.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index fce2e22..eb4ab0d 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -4518,8 +4518,10 @@
         if( ( status != PSA_SUCCESS ) &&
             ( opt.query_config_mode == DFL_QUERY_CONFIG_MODE ) )
         {
-            mbedtls_printf( "Failed to destroy key slot %u - error was %d",
-                            (unsigned) psk_slot, (int) status );
+            mbedtls_printf( "Failed to destroy key slot %u-%u - error was %d",
+                            MBEDTLS_SVC_KEY_ID_GET_OWNER_ID( psk_slot ),
+                            MBEDTLS_SVC_KEY_ID_GET_KEY_ID( psk_slot ),
+                            (int) status );
         }
     }
 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED &&