Four small changes:
1. The notice about 1.4.0 was stale now that we've released newer
   version(s).
2. The build-from-source instructions were hard to copy/paste because
   they required interactive input.
3. The CSI driver wasn't mentioned in the docs.
4. The AUR repo is unmaintained (not updated since last July), so we
   shouldn't point customers to it.

I also did a little bit of minor clarifying/editing.

Signed-off-by: James Bornholt <bornholt@amazon.com>