Use delta query to track changes

Would it be possible to add a delta query option to the "getters" in this package?
It'd be nice to be able to easily operate on the new items since the previous run of code.

https://learn.microsoft.com/en-us/graph/delta-query-overview#use-delta-query-to-track-changes-in-a-resource-collection

I could imagine:

```
site <- Microsoft365R::get_sharepoint_site()
site$get_list(list_id, delta=TRUE)
```

or

```
site <- Microsoft365R::get_sharepoint_site()
site$get_delta_list(list_id, delta=odatadeltaLink)
```

Start with the Microsoft Graph delta-query documentation and the existing get_sharepoint_site() and site$get_list() entry points. Compare the proposed delta=TRUE and odatadeltaLink forms, then define how callers receive new items and continue from the returned delta link. Done means the SharePoint list getter can track changes across runs as described.

Written by the indexing model from the issue text.