[spreadsheet] properly paste the data in the format 'yyyy-MM-dd hh:mm:ss' and similar.
requested to merge work/215-wrong-result-when-pasting-datetime-values-in-the-yyyy-mm-dd-hh-mm-ss-format into master
When pasting DateTime data in the format 'yyyy-MM-dd hh:mm:ss' and similar, it get's split first because of the space separator. We check whether we have such a situation and merge the first two columns to get the proper value, for example "2018-03-21 10:00:00" and not "2018-03-21" and "10:00:00"