cli: align UTF-8 strings properly

Not all utf-8 characters occupy 1 screen column. Some may be 2-column
wide, some are unprintable - zero columns.

cli/src/utils.h

@@ -28,6 +28,7 @@
 int matches (const char *cmd, const char *pattern);
 int next_arg (int *argc, char ***argv);
 char *ssid_to_printable (const char *str, gsize len);
+int nmc_string_screen_width (const char *start, const char *end);
 GArray *parse_output_fields (const char *fields_str, const NmcOutputField fields_array[], GError **error);
 gboolean nmc_terse_option_check (NMCPrintOutput print_output, const char *fields, GError **error);
 void print_fields (const NmcPrintFields fields, const NmcOutputField field_values[]);