Lift necessity to patch xarray scaling and timedelta decoding

[j-haacker]

Is your feature request related to a problem? Please describe.
Currently, xarray needs to be patch to allow opening ESA's L1b netcdf files. Further, two warnings are issued by xarray.

Describe the solution you'd like
A backend should be used that is able to read the concerned scaling factor and decode the time stamps.

Additional context
xarray hints at a possible solution saying one should use an appropriate CFTimedeltaCoder. I suspect this would fix only one of the issues, nut maybe using a different backend for reading the data fixes both?

[j-haacker]

Is hopefully fixed for xarray version after pydata/xarray#10050.