smartsheet: implement export (create new sheet from interm. struct)
smartsheet: implement export (create new sheet from interm. struct)

There is still some problem with calculating working day (+1 offset
sometimes).

RedHat-Eng-PGM/schedules-tools,RedHat-Eng-PGM/python-schedules-tools,RedHat-Eng-PGM/python-schedules-tools,RedHat-Eng-PGM/schedules-tools,RedHat-Eng-PGM/python-schedules-tools,RedHat-Eng-PGM/schedules-tools