Add GetAllAsync overload without parameter simplify getting all or by keys

[ronaldbarendse]

As mentioned in #16230 (comment), changing GetAllAsync() to return all data types if no keys are specified requires conditional checks when supplying a dynamic list of keys (as an empty list of keys would now return all data types, instead of 0).

To avoid having to manually check the length of the list of keys, this PR adds an overload without the parameter that returns all data types and reverts the previous method to only return data types for the specified keys (so an empty list of keys results in an empty list of data types again).

This should also prevent similar bugs in the future (or in packages). The only discrepancy would be that GetAll(params int[] ids) still returns all data types if an empty list of IDs is specified), but this methods has already been obsoleted.

[kjac]

Hi @ronaldbarendse

Thanks for this ❤️ sorry it's taken a while to get back to you.

While this makes a ton of sense, we are too close to V14 to make this change. We also would like to see this change on every service layer that exhibits this behavior.

In short: We are going to move this task to the backlog. In the future we'll introduce the following methods on the relevant service layers:

• GetAllAsync: Has no parameters, always returns all items.
• GetManyAsync: Accepts a params parameter of keys, returns only the requested items - and none, if the params parameter is empty.