Handle the case with non-existing directory specified in the csv filepath for collecting statistics

[mbakholdina]

When collecting SRT csv statistics, if the filepath contains the folder name _some_folder/filename.csv and this folder does not exist, srt-xtransmit does not handle this situation: 1. There is no error and it starts transmission, but 2. No folder is created and as a result no csv file is created.

I think it would be useful to create the directory in this case.

[mbakholdina]

An addition: This behaviour takes place in case of using generate subcommand. In case of using receive, there is an error that the directory _some_folder does not exist.