Data Managers meeting discussion point #5: temporalCoverage

**Proposed issue for `temporalCoverage`**
Current guidelines do not allow to define an interval of time prior to 15th October 1582 as per [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) standard.

**Original comment**
Note that there may be paleo-climate or paleo-environmental studies that contain data older than the last 2000 years, meaning a time interval including BCE/BC. Typical examples are Holocene sediment profiles. ISO 8601 can handle this using negative numbers for BCE/BC years, so it should not be a problem but it is something to keep in mind and be prepared for (five-digit format for Years).

**Proposed solution**
Provider may express temporal intervals prior to 1582 by using the DateTime data type and URL as per science-on-schema.org [guidelines ](https://github.com/ESIPFed/science-on-schema.org/blob/master/guides/Dataset.md#temporal-coverage)