Let's have it under `base`, as we want to add a few overlays in order to
make sure this will work as expected with kubernetes flavours such as
`k3s`, or `rke2`.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

In order to be able to override this accordingly to the kubernetes
flavour being used, we want to make it slightly more flexible on our end
and pass the directory instead of the file itself.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

We're doing this in order to, later on this series, use kubectl to
determine which kubernetes flavour we're running on the node.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

Right now this is very basic and simply will let us know whether we're
running on a node that's using containerd or not.

This ended up with the move of parts of the logic on detecting
containerd and containerd configuration files being removed from a few
specific functions and being put directly into the main one.

In the coming patches of this series we'll expand it to also detect
other kubernetes flavours, such as `k3s` or `rke2`.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

With these changes we're now able to also run the nydus-snapshotter
daemonset on `k3s` clusters.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

With these changes we're now able to also run the nydus-snapshotter
daemonset on `rke2` clusters.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

Differently than `k3s` or `rke2`, getting `k0s` to work as expected is
quite tricky, as it relies on a drop-in configuration file, and I'm not
so confident we can easily drop-in a file with all the needed bits.

With this in mind, at least for now, let's just error out in case k0s is
used, as at least this will make sure that the users will at least have
a clue on what's been gone wrong.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

Let's make sure the ClusterRole, ClusterRoleBinding, and the correct
environment variables (such as NODE_NAME) are properly set as part of
the E2E tests.

Signed-off-by: ChengyuZhu6 <chengyu.zhu@intel.com>
Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>