feature: kernel: provide set of config deviations from defconfig instead of monolithic configs

[kaniini]

At present, our stripped down domU kernel for running container workloads uses large monolithic configs.

Instead, we should look at what Alpine does for the linux-rpi kernel and do similar: https://git.alpinelinux.org/aports/tree/main/linux-rpi/APKBUILD#n86