Previously, minikube has been shipped with the default CNI config
(/etc/cni/net.d/k8s.conf) in its rootfs. This complicated a lot
when using a custom CNI plugin, as the default config was picked
by kubelet before the custom CNI plugin has installed its own CNI
config. So, the end result was that some Pods were attached to a
network defined in the default config, and some got managed by
the custom plugin.

This commit introduces the flag "--enable-default-cni" to
"minikube start" to trigger the provisioning of the default CNI
config.
Signed-off-by: NMartynas Pumputis <m@lambda.lt>

* Change restart policy on gvisor pod

Change the restart policy on the gvisor pod to Always. This way, if a
user runs

minikube addons enable gvisor
minikube stop
minikube start

when the addon manager tries to restart the gvisor pod, it will be
restarted and gvisor will start running automatically. This PR also adds an
integration test for this functionality.

* Test stop and start

* Revert test to delete

Revert test to delete for now, for some reason "stop" and then "start"
is failing both locally and in Jenkins for VirtualBox with a "panic test
timed out after 30 min" error

This PR adds the code for enabling gvisor in minikube. It adds the pod
that will run when the addon is enabled, and the code for the image
which will run when this happens.

When gvisor is enabled, the pod will download runsc and the
gvisor-containerd-shim. It will replace the containerd config.toml and
restart containerd.

When gvisor is disabled, the pod will be deleted by the addon manager.
This will trigger a pre-stop hook which will revert the config.toml to
it's original state and restart containerd.

* Add integration test to make sure minikube starts and stops with containerd
* Skip testing containerd if using none driver

* even longer timeout + timeout error is retriable now
* fix for debugging when tunnel test has issues

* Restrict TestDocker commands to 10 minutes of total runtime.
* Hide unneccesarily scary delete error

Small improvements to debugging and reducing integration test flakiness: 
* added logging to kubeadm init in the SSHExecutor
* increasing timeout for RBAC creation via the kubernetes client set 
* only log tunnel output to test logger

This change is a bit of a hack to make IP routing work over the virtio-net interface - it forces the virtio-net interface (bridge100) created by hyperkit/xhyve to reset via removing and readding the single member of the interface. Without this "reset" packets are just simply lost most of the time, despite a completely healthy IP route.

This error was also the reason for a large percentage of our integration test failures. While reducing the flakiness of tunnel related tests I also increased the timeout requirement and adding retries to the nginx request in TestTunnel.

This test typically takes <30s to execute, so 180s should leave plenty
of margin for error.

This commit introduces a new command, `minikube tunnel`, a LoadBalancer emulator functionality, that must be run with root permissions.

This command:

* Establishes networking routes from the host into the VM for all IP ranges used by Kubernetes.
* Enables a cluster controller that allocates IPs to services external `LoadBalancer` IPs.
* Cleans up routes and IPs when stopped (Ctrl+C), when `minikube` stops, and when `minikube tunnel` is ran with the `--cleanup` flag

These tests reliably cause a "panic: timed out" condition due to
hitherto unknown reasons. See issue #3200 for context.

dlorenc mentioned that this test never worked, so when I re-enabled it
recently for all platforms in af61bf79,
it introduced a persistent test failure for darwin.

I'll leave issue #3200 open until we are able to re-enable this test.

- Updates Ingress-Controller Version to 0.19.0
- Adds Service Account for Ingress-Controller
- Adds Support for Prometheus
- Fixes bug with TCP/UDP ConfigMaps not Loading
- Adds more resource limits to default-backend
- Use new ingress class name
- Use app.kubernetes.io/xxxxxxxxxxx labels

This provides an additional level of security, by enforcing host checking, applying port randomization, and requiring explicit user intent to expose the service to the host.

This reverts commit af61bf79.