* [alpha] Improve Flex volume deployment

  * Flex volume driver deployment is simplified in the following ways:

    * New driver files can now be automatically discovered and initialized without requiring a kubelet or controller-manager restart.

    * A sample DaemonSet to deploy Flexvolume drivers is now available.

- Server Side Apply now treats all <Some>Selector fields as atomic (meaning the entire selector is managed by a single writer and updated together), since they contain interrelated and inseparable fields that do not merge in intuitive ways. ([#97989](https://github.com/kubernetes/kubernetes/pull/97989), [@Danil-Grigorev](https://github.com/Danil-Grigorev)) [SIG API Machinery]