Kernel params

This pull requests changes the boot script slightly that allows passing all the config parameters as kernel parameters. This makes it possible to boot and install the system via PXE and configure it without manual interaction.

It also adds some additional options for disks, namely `all_disks` which will use all the disks to install a system which is very helpful for automated installation. In addition it comes with a new profile for disks raid10+2 for a setup with striped mirrors and two spares.

The `bootparams.md` file explains the parameters used.