Introduce two variables `Aviso_DT_dir` and `Eurec4A_NRT_dir` to
replace the single variable `large_input_dir`. This should remove the
need to create symbolic links to the files in these directories.

I had the directories `n_dates_1` and `n_dates_14`, but they did not
evolve with the code and there was not much traceability.

Write files `grid_nml.txt`, `used_config_nml.txt` and `n_slices.txt`.

This will be useful to create `n_dates_1` and `n_dates_14`. It should
be faster for this purpose than using the more general script `filter.py`.

Not used since commit cd8df9d2.

Use method `ishape_range` in function `select_ishapes`.

I do not see the point any longer of that distinction. If the date
option is used, we could do some checks on the date but not
specifically for the case of a single date in the slice.

Dictionary instead of list, following update of `test_compare.py`.

This is much too long for completely different files.

Apart from the fact that `Global_1993_2021` was obtained with a more
recent version of the code, there is not much point in keeping a
separate experience for the year 1993.

This is useful because, for the year 2021, the last part of Aviso file
names varies.

Define it inside the function since we only need it here and we
already have the argument `first_file`. Simpler and clearer.

Clearer and simpler. Also it avoids appending to a previous
`timings.txt` file.

The bug comes from commit 1cfed454.

`n_max_cont` is just the maximum number of contours in `cont_list`,
and `n_cont` is the actual number.

Create `cropped.nc` and `unpacked.nc` in the slice directory, so that
several processes running `inst_eddies.py` for different slices can
run in parallel.

Instead of symbolic links. We want to avoid creating symbolic links
above SHPC because we want to run several instances of `inst_eddies`
in parallel.

So that several processes running `inst_eddies` for different slices
can run in parallel.

So that several processes running `inst_eddies.py` for different
slices can run in parallel.

So the script can write to a slice other than 0.

On second thought, I find the default value confusing. We are
reverting commit b328ab6f.

The attribute written was always true.