This reverts commit 1bd0f379.

This was created to migrate Turris OS 4.0-alpha* releases. The first
supported version 4.0-beta1 already contains correct path with board
specific path so there is no need to preserve these obsolete ones.
Non the less they are also wrong with additional introduced changes.
They point to pkglists in invalid location.

This requires also removal of code on build server to not use --obsolete
option and to not deploy those.

This should help us to debug system configuration better to see what
exactly was targeted version. This also helps users to see what they are
dealing with. It in some sense informs them if they are upgrading to new
version or if that is just packages change (because of configuration
change) in same release.

These are temporally lists to redirect previous versions of updater to
correct locations.

This creates lists that can be included in to each other. This is done
by hack that original script calling one of these lists passes base URI
to access sources and that is later reused. This is how relative URI
should work in future but it is not completed now so we can overcome it
this way and have almost same support.

This also means that we no longer have to specify target branch for
lists because it no longer matters.

Fallback branch is for now dropped because we are not doing small build
at the moment. We should in future return to them but they will be
implemented differently then fallback branch is.

This also does some base list cleanup.

This is better idea as having #!/bin/bash -e is fragile. Anyone can run
this script with bash -x file and that way unintentionally disable -e
flag.