Convert to xarray on push

Conversion to xarray was possible during pull only, as info was possibly not available yet. However, with push forwarding (notify_targets), push is not possible anyway unless infos were fully exchanged.

Thus, we can (theoretically) convert during the push.

This, however, results in conflicting time steps (which is to be expected). Without a time adapter, simply the last pushed data is retrieved when pulling.

Solved that by ignoring the time value (not it's presence!) during input pull. Advantage over the old version is that the data has the actual time of the push attached.