0840 Unclear which entity should be used to record the "spudding" date of a well

The entity which is intended to contain "spud" data and "completion" data is not at all obvious. Locations in the Activity model and the Facility model appear appropriate, if ambiguously labelled. Some clarity would be desirable here.

Add starting and endind dates for well objects

Attribute describing the start and end dates for well, wellbore, well completion and wellbore component facility were added.

Added objects:
well.abandonment_date (Attribute)
well.spud_date (Attribute)
well_completion.abandonment_date (Attribute)
well_completion.completion_date (Attribute)
wellbore.abandonment_date (Attribute)
wellbore.completion_date (Attribute)
wellbore_component_facility.end_date (Attribute)
wellbore_component_facility.start_date (Attribute)