Switch to modules_install or cleanup the module compression handling

[evelikov]

As mentioned in #318 we have a convoluted and buggy compressed/uncompressed module handling.

One option is to carefully audit and fix it up - the other to switch to module_install. The latter option will give us module stripping and signing for free.

There might be some specific reason why dkms tries to do all of that itself instead of relying on the kernel build system - @scaronni if you have any pointed, or know people who might know please let me know.

[scaronni]

As far as I know, this is just historical stuff and has no particular reason to exist in its current form, it dates back to ~2002?

I think the main reason was just supporting old EOL distributions and other OSes (Hurd).

[evelikov]

Ack, sounds like we could add a few more distros and/or versions in the mix and see how badly things explode.

There's a good argument to support EOL stuff, yet within reason IMHO. For really ancient ones it looks like a disservice for ourselves and the respective users.