Add an option to install the appropriate kernel headers

[wc7086]

Some software, like virtualbox, will try to install kernel modules at the same time, and without the headers some features will not work because the kernel modules cannot be installed. I think should add an option for users to install kernel headers, so that when changing the kernel version to be installed, there is no need to change the kernel header version in the package list.

The following code should be decoupled so that the user force a selected installation of the kernel headers along with the selected installation of the Nvidia kernel module. https://github.com/archlinux/archinstall/commit/ffc43bc0411c71f84fa1c7e52204c2b20e311429

[dylanmtaylor]

Might be a good candidate for an --advanced feature if we add it, since most users won't need this and it'll add more selections to the installation

[svartkanin]

Maybe it should be renamed to "--experimental" all together ?

[dylanmtaylor]

Maybe it should be renamed to "--experimental" all together ?

I think the current name is sufficient. Additionally, changing the name would be confusing to users.