tune, de-duplicate and make accessible modules from initramdisk after system boot

[dorvan]

like what we do in our project "AnthillaOS", kernel package it's not only the kernel file + ramdisk, but there is always a modules squash file, and a firmware squash file, to make kernel separate from system image and pluggable, but, in many situation ramdisk (from genkernel) includes the modules already present in the modules squash file, will be great make an hybrid initramdisk, usable by the kernel and usable by mounting after the boot as modules squash file. the same for firmware, if is not possible including a procedure in linuxrc to check squash files passed by kernel command line.

to have a live pluggable os