Extend support for WS2019 nanoserver images
Right now, all nanoserver images have 18 months of support, and this makes sense for SAC versions. However this is also applying now to LTSC versions.
Hence, if someone needs a stable environment (Windows Server 2019 LTSC Hosts) and want to use containers, they are forced to use the servercore images, as nanoserver are out of support.
It makes no sense to have WS2019 with 10y support, and the corresponding nanoserver image with 18m support.