rename and extend convert_idx_to_tuple
rename and extend convert_idx_to_tuple

Support for more input values and function is renamed from _convert_idx_tuple
to _convert_idx_to_tuple.

Signed-off-by: Heiko Thiery <965a85d69f7aa0aa83bbdecf1b37e17133c01ac3@kontron.com>

kontron/robotframework-snmplibrary