Remove Matimba divergence example from 'example_tropomi_Matimba.ipynb' and update example in 'example_divergence.ipynb'; fix assuming CO2 in unit conversion

Make divergence method more flexible working with TROPOMI data

See merge request empa503/remote-sensing/ddeq!12

(cherry picked from commit 2d320e4e)

Replace scipy.vectorize with np.vectorize in era5.py

See merge request empa503/remote-sensing/ddeq!9

Merge fix for not using provided pixel size in CSF method

See merge request empa503/remote-sensing/ddeq!8

Fix not using pixel size for bounds in CSF method

See merge request empa503/remote-sensing/ddeq!7

Fix download TROPOMI

Closes #1

See merge request empa503/remote-sensing/ddeq!6

Add documentation

See merge request empa503/remote-sensing/ddeq!5