Automatic merge from submit-queue (batch tested with PRs 55648, 55274, 54982, 51955, 55639). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Kubelet: Relative paths in local config file

Resolve relative paths against the config file's location.

Issue: #55644
Related comment: https://github.com/kubernetes/kubernetes/pull/53833#issuecomment-344009912

Will add the same behavior for dynamic Kubelet config in a future PR, see issue #55645.

```release-note
Relative paths in the Kubelet's local config files (--init-config-dir) will be resolved relative to the location of the containing files.
```