[SCHEMA] End date field to complement established date

[adambuttrick]

Version
v2

Describe the problem you would like to solve
Our schema includes an "established" field to indicate when an organization was founded, but there is no way to record when an organization ceased operations or became inactive. While the status field can be updated to reflect that an organization has ceased operating, there is currently no way to know the date when it became inactive.

Describe the schema change that you would like in order to solve the problem

Add a new field to the ROR schema to reflect an organization's end date. This field would:

1. Be optional
2. Use the same date format as other date fields in the schema.
3. Represent the date when an organization became inactive or ceased operations
4. Complement the existing "status" field, providing more precise temporal information when the status is "inactive"

A potential example:

"end_date": {
    "type": ["null", "number"],
    "default": null
}

Who would benefit from this change?

1. Users looking for more accurate historical or bibliometric analyses of organization life cycles
2. Funders: To track the status and longevity of funded organizations
3. Publishers and discovery services: For maintaining accurate metadata for publications from now-inactive institutions

Additional information
Requested by ABES - https://ror.org/027xymc69