Definition of temporal resolution unclear - missing "now" option

Description of the issue

First of all - the Issue selection is missing something like "Question". But maybe every question also enhances the project 😊

The current schema has an example https://github.com/OpenEnergyPlatform/oemetadata/blob/c3dcc0d8e697baeaea81ae63e07a6da58ec3ae3f/oemetadata/latest/example.json which shows some information about temporal data. Besides, there is also a start and end of data.

In general the main question is:

• how should "now" be represented in the data and where?

To make two examples, I wonder how specific use cases should be covered:

• Marktstammdatenregister:
  • Data included contains data from ~1900 until now
  • the snapshot has a date of which it was published
  • each table in the data (package) might have different start and end times (which are rather uninteresting)
  • start of the MaStR was in 2019

What should I put here as a "publicationDate" and in the general start and end field or in the specific ones?

• ENTSO-E
  • Data included ranges from 2015 until now and is continuesly updated
  • The metadata would need constant updates as each update of the data should be reflected
  • Timeseries availability could be added for each timeseries in the temporal part

Ideas of solution

Describe possible ideas for solution and evaluate advantages and disadvantages.

Workflow checklist

• I am aware of the workflow in CONTRIBUTING.md