Add cmorizer for the Global Lakes and Wetlands Database (GLWD) version 2.0 dataset #4109
Description
Add a downloader and formatter for the Global Lakes and Wetlands Database (GLWD) version 2.0 dataset (https://www.hydrosheds.org/products/glwd) containing the wetlandFrac variable (see table entry at https://github.com/ESMValGroup/ESMValCore/blob/a748547e7b93ef84aaff83eb4031deb2abdda5a1/esmvalcore/cmor/tables/cmip6/Tables/CMIP6_Emon.json#L5885)