Declare a psa_key_file_id_t layout with an owner field

Declare the owner as psa_key_owner_id_t, of which an implementation
must be provided separately.

Make this a configuration option
MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER, to make the conditional
compilation flow easier to follow. Declare it in config.h to
pacify check_names.sh.

Support for a specific implementation of psa_key_owner_id_t in storage
backends will come in a subsequent commit.
diff --git a/library/version_features.c b/library/version_features.c
index ad3f937..2bfecf0 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -411,6 +411,9 @@
 #if defined(MBEDTLS_PSA_HAS_ITS_IO)
     "MBEDTLS_PSA_HAS_ITS_IO",
 #endif /* MBEDTLS_PSA_HAS_ITS_IO */
+#if defined(MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER)
+    "MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER",
+#endif /* MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER */
 #if defined(MBEDTLS_MEMORY_DEBUG)
     "MBEDTLS_MEMORY_DEBUG",
 #endif /* MBEDTLS_MEMORY_DEBUG */