Re-introduce from and to date

[paolap]

If we can use templates (https://opensearch.org/docs/2.0/opensearch/search-template/) that users can load to do complex queries than we can re-introduce from-date to-date instead of temporal coverage.
Currently a range date is accepted by the date field but the mappings still consider it as a date, this means that the query on temporal coverage doesn't work as expected.