of non-standard grids

[pyicon_dwd] Difference plots for the atmosphere, area weighted horizontal mean of fields, new fields for atmosphere plots, etc.

See merge request m300602/pyicon!7

[pyicon_dwd] Rewrite optional restriction of time-series plots to the intervall tave_int: introduce use_tave_int_for_ts. The tools/run_qp_* scripts are also updated accordingly.

[pyicon_dwd] qp_compare_atm_dwd.py: skip SST and sea-ice fraction if the difference between 2 exps is zero

[pyicon_dwd] small fix path_data --> path_data1 for printout when checking available data for period t1,t2

[pyicon_dwd] Use time_mode_atm=num2date. Update pyicon/quickplots/qp_compare_atm_dwd.py accordingly too.

-- move new atmo-plot developments from pyicon/quickplots/old_qp_driver.py to pyicon/quickplots/qp_driver.py.
-- temporarily, create atm-, and cpl-related run_qp_driver*_old.sh scripts, which still use pyicon/quickplots/old_qp_driver.py

[pyicon_dwd] Add namelists to link /additional information/ and also fill in the link /pyicon documentation/.

[pyicon_dwd] Add horizontal maps of TOA sw/lw net fluxes, surface latent/sensible heat fluxes, sea-ice fraction, SST. Both in single mode and comparison mode.

[pyicon_dwd] In qp.timeseries, plot time series only up to t2. Allow printing min, max, mean, std for both experiments in qp.timeseries_comp.

[pyicon_dwd] Fix for Overview table if using ICON-A (old MPI) outputs. Replace gboeloen to icon-sml in tools/run* where possible.