Improve use of OFFSET, LIMIT in CosmosDBRepository class

Currently, all our query operations use `OFFSET LIMIT ` in the query string. This works ok at the moment, as the number of items in our containers is "little" (is not in the order of 100.000 or 1'.000.000).

In containers like `time_entry` the number of items grows quickly. Combined with recurrent use of OFFSET & LIMIT in query operations, we could experiment some performance issues and high costs, in the future.

We should improve this, as a preventive action.

References:
- https://tusharsharma.dev/posts/api-pagination-the-right-way
- https://phauer.com/2017/web-api-pagination-continuation-token/#offset-pagination
- https://docs.microsoft.com/en-us/azure/cosmos-db/sql-query-offset-limit