Automatic merge from submit-queue (batch tested with PRs 50932, 49610, 51312, 51415, 50705)

Allow running kube-proxy as a DaemonSet when using kube-up.sh on GCE

**What this PR does / why we need it**:
From #23225, this PR adds an option for user to run kube-proxy as a DaemonSet instead of static pods using GCE startup scripts. By default, kube-proxy will run as static pods.

This is the first step for moving kube-proxy into a DaemonSet in GCE, remaining tasks will be tracked on #23225.

**Special notes for your reviewer**:
The last commit are purely for testing out kube-proxy as daemonset via CIs.

cc @kubernetes/sig-network-misc @kubernetes/sig-cluster-lifecycle-misc 

**Release note**:

```release-note
When using kube-up.sh on GCE, user could set env `KUBE_PROXY_DAEMONSET=true` to run kube-proxy as a DaemonSet. kube-proxy is run as static pods by default.
```