[PATCH v3 14/18] lib: Add a function to convert a string to a hex value

[art]

OK will be usefull

Reviewed and Tested on -master Mon 18 Oct 2021 04:40:29 PM CST
Reviewed-by: Artem Lapkin <email2tema at gmail.com>
Tested-by:  Artem Lapkin <email2tema at gmail.com>