Automatic merge from submit-queue (batch tested with PRs 49874, 56919, 57246). 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>.
Enable support for etcd3
**What this PR does / why we need it**: With this PR juju deployments of kubernetes can use both etcd2 and 3.
**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**: Lets not merge this immediately. Lets wait for next year.
**Release note**:
```NONE
```
ee43f7c34e