[dv/str_utils_pkg] add byte_to_str function
[dv/str_utils_pkg] add byte_to_str function

This commit adds a `bytes_to_str` function in the `str_utils_pkg` that
allows us to convert a bytestring back into string representation.

Signed-off-by: Udi Jonnalagadda <790cd677b6a22a419ffcfe0eb4293d8866eb70c9@google.com>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan