Function wdinfo::file_status::rename_log_with_timestamp

pub fn rename_log_with_timestamp(pathstr: &str) -> Result<(), &'static str>

each run with separate log file by timestamp as suffix in file name

• log4rs will create file if not exist, but just append if exist
• If log4rs just create it, it is empty, no backup needed
• Create suffix using yyyymmdd_HHMMSS timestamp
• Copy log file to backup file and delete it (like rename)
• log4rs will still append (create if not exist)