CSPNet: Add Kaggle presets to preset map

[mrinalghoshh]

following CSPNet presets are listed on kaggle but missing from KerasHub's preset map.
csp_darknet_l,
csp_darknet_l_imagenet,
csp_darknet_m,
csp_darknet_s,
csp_darknet_tiny,
csp_darknet_tiny_imagenet,
csp_darknet_xl