Automatic merge from submit-queue. 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>.
Refactor storage factory config with Complete().New() flow
**What this PR does / why we need it**:
1. Split `BuildStorageFactory` constructor into `Complete().New()` flow to build an instance for etcd storage.
2. Put `EtcdOptions` and `StorageSerializationOptions` into a `StorageFactoryOptions` for a more reasonable structured config object.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
**Special notes for your reviewer**:
Generally, my idea is to split the huge code in [https://github.com/kubernetes/kubernetes/blob/master/cmd/kube-apiserver/app/server.go](https://github.com/kubernetes/kubernetes/blob/master/cmd/kube-apiserver/app/server.go) into somewhere else making more sense :)
**Release note**:
```release-note
NONE
```
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