Add Soil Moisture Layer for South Africa

[EmileSonneveld]

We already have the following layer, but this is not accessible in South-Africa. Need to verify if it contains the good values too:
https://land.copernicus.eu/global/products/ssm

This is needed to calculate the CDI for the ANIN project

[EmileSonneveld]

This dataset looks a lot like the data from here: https://edo.jrc.ec.europa.eu/gdo/php/index.php?id=2112 (World > Ensemble Soil Moisture Anomaly)
But realtime information appears to be missing here

[EmileSonneveld]

2022-08 matches between GMV results and GDO:

Open EO image generated using this snippet:

# inspired on https://git.vito.be/users/lippenss/repos/workspace/browse/2023/PEOPLE/udp-reduce_temporal.ipynb
cube = connection.load_disk_collection(
    format="GTiff",
    glob_pattern="/data/users/Public/emile.sonneveld/SMA_layer/smant_m_wld_*_t/smant_m_wld_*_t.tif",
    options=dict(date_regex='.*_(\d{4})(\d{2})(\d{2})_t.tif'),
)