Documentation of pagination in missing in the metadata spec

[Pierre-VF]

On the metadata spec ( https://github.com/carbon-data-specification/Power-Systems-Data/blob/main/specifications/cdsc-wg2-03.md ), the semantics of the pagination is undocumented.

It might be a good idea to indicate how this is expected to work in the future as part of the "Response Object" definition (e.g., ("next": null, "previous": null) indicates that pagination is not used, while relevant pagination would look like ("next": X, "previous": Y) where X and Y are to be replaced by realistic values for the example)