image_depmod: add class to run depmod on image modules
image_depmod: add class to run depmod on image modules

When collecting modules from out-of-tree builds, one must run depmod at
image creation time to resolve module dependencies. E.g. with wifi
drivers from linux-backports fails to load at first boot if dependencies
are missing.

sknsean/core,sknsean/core,sknsean/core,sknsean/core,sknsean/core