Accommodate for satellite data storing coord transform reference as a coordinate

[AUdaltsova]

Satellite data uses geostationary coordinates, which means it needs a reference point (satellite position) to transform to lat lon correctly. We currently store this as an "area" attribute, which leads to some problems (for now only in IODC service, read more in this satip issue).

We will be moving to a more robust way of storing this, as a time-dependent coordinate (see this issue in sat consumer). It will be a bit before this is implemented, but we will need to accommodate for it in code here in ocf_data_sampler/select/geospatial.py. We will keep the attribute method as well for backwards compatibility.

This issue is on hold until the sister issue in sat consumer is completed.

[dfulu]

Here's another approach to this that I just learned about. We make multiple datasets, one for each satellite position, and we concatenate them. This would require minimal code changes, and minimal changes to our data structure. And it may be sufficient if the satellite position changes only a few number of times