As a user, I want Harvest automatically convert date / time fields to ISO format supported by Elasticsearch

[tdddblog]

Motivation

...so that I can load my data into Elasticsearch

Additional Details

Current version of Harvest only converts fields containing "date" in the field name, such as start_date_time. Fields like earth_received_start_time are not converted and documents with those fields could not be loaded into Elasticsearch. Harvest should convert all date / time fields based on data dictionary field definition.

Follow-on to #55

Acceptance Criteria

**Given a date/time field defined in an LDD
**When I perform harvesting of products referring that LDD
**Then I expect all date/time fields converted to "ISO instant" format supported by Elasticsearch.

Engineering Details

• Harvest should be able to read registry data dictionary from Elasticsearch registry-dd index.
• If a field data type is one of PDS4 date/time types, the field value should be converted to "ISO instant" format.

[jordanpadams]

closed per PRs above