[feature] Grassim management practices

Summary

There may be a clarification needed within the documentation of Grassim.

Current behavior

There is a mention in the doc to the following element to be added when the management practice is by "date". - Requires: - cut_dates(list of strings indd-mmformat, e.g.,['15-04', '15-05']). Nevertheless, it is not fully clear if this attribute should be added to the yml file or elsewhere.

Desired behavior

Add the following management plan within Grassim

initial_dates = ["18-05", "23-06", "17-07", "18-09", "14-11"]

Sources

Linked features or branches

There is not yet a branch created for this purpose. We can quickly discuss it during the PASAthon in order to report the solution in the ticket.

Duplicate of https://gitlab.uliege.be/pase-dev/pase/-/issues/70. Should be handled in the public repo since pase_dev is not to date.