pyicon/pyicon_plotting.py: Added new plotting object to facilitate generation of axes and passing them to plotting routinse.

pyicon/pyicon_plotting.py: Always use always interp_to_rectgrid_xr instead of using both interp_to_rectgrid_xr and interp_to_rectgrid.

pyicon/quickplots/qp_arctic_budgets.py: Bug fixes to make it work with latest versions of pyicon and matplotlib.

pyicon_plotting.py: Added prototype function pyic.plot which is supposed to become a generic function for ICON plots based on xarray DataArrays. So far only horizontal plots are supported.

quickplots: Make correct time averaging possible for data where the time date data associated to the averaged data is within or at the beginning of the time averaging period (e.g. as it is the case for data post-processed with mkexp).

pyicon_tb.py: In calc_vertical_interp_weights allow interpolations also if field is decreases along axes.

Some fixes for atmospheric plots, datetime64_to_float, temporarily use old_qp_driver.py to prevent errors due to new mapping for ocean data in qp_driver.py

See merge request m300602/pyicon!5

requirements_py39_cartopy19.yml, act_pyicon_py39.sh: Try to use cartopy 0.19 instead of 0.20.x to avoid performance drawbacks from the 0.20.x version.

[pyicon/pyicon_tb.py] Revert pyicon/quickplots/qp_driver.py to master. Also revert pyicon/quickplots/old_qp_driver.py to master with the exception that the Overview tab is taken out of the if do_ocean_plots in order to have that also when only atmo plots are done. Also the order of variables in tab_overview is changed wrt master.

[pyicon_dwd] Minor changes in old_qp_driver.py and qp_driver.py to improve browsing (overview tabs) in case only atmo plots prepared.

[pyicon_dwd] improve run_qp_driver*dwd*, use old_qp_driver.py to prevent errors due to new mapping for ocean data

[pyicon_dwd] Bugfixes, add QP script to plot both ocean and atmosphere at the same time (or optionally only one of them).