Function populate_table_timelogs_by_label 

pub fn populate_table_timelogs_by_label<'a>(
    time_logs: &[TimeLog],
    label_filter: Option<&HashSet<String>>,
    label_others: Option<&Label>,
) -> (Vec<Vec<String>>, &'a [&'a str])

Assemble data for a table with time statistics for the given labels. Returns a tuple of the table data and the table header.