Implements KEP 2000, Graceful Node Shutdown:
https://github.com/kubernetes/enhancements/tree/master/keps/sig-node/2000-graceful-node-shutdown
* Add new FeatureGate `GracefulNodeShutdown` to control
enabling/disabling the feature
* Add two new KubeletConfiguration options
* `ShutdownGracePeriod` and `ShutdownGracePeriodCriticalPods`
* Add new package, `nodeshutdown` that implements the Node shutdown
manager
* The node shutdown manager uses the systemd inhibit package, to
create an system inhibitor, monitor for node shutdown events, and
gracefully terminate pods upon a node shutdown.
Nit: remove capitalization of preferred
Remove line from kubelet and add to separate PR for easier merge
nit: dependency added to separate PR
Add check to ensure strict policy cannot be set without feature gate enabled
Topology Manager runs "none" policy by default.
Added constants for policies and updated documentation.
When node lease feature is enabled, kubelet reports node status to api server
only if there is some change or it didn't report over last report interval.
Automatic merge from submit-queue (batch tested with PRs 67950, 68195). If you want to cherry-pick this change to another branch, please follow the instructions here: https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md.
Consolidate componentconfig code standards
**What this PR does / why we need it**:
This PR fixes a bunch of very small misalignments in ComponentConfig packages:
- Add sane comments to all functions/variables in componentconfig `register.go` files
- Make the `register.go` files of componentconfig pkgs follow the same pattern and not differ from each other like they do today.
- Register the `openapi-gen` tag in all `doc.go` files where the pkg contains _external_ types.
- Add the `groupName` tag where missing
- Fix cases where `addKnownTypes` was registered twice in the `SchemeBuilder`
- Add `Readme` and `OWNERS` files to `Godeps` directories if missing.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
/assign @sttts @thockin
