Fix multinode networking when using cni=auto

[scott-the-programmer]

Fixes https://github.com/scott-the-programmer/terraform-provider-minikube/issues/131

Currently, setting up multiple nodes with cni=auto exhibits inconsistent behaviour due to not providing enough information to chooseDefault function in minikube.

There's 3 key pieces we're missing

A) the container runtime, which should default to docker (previously blank) B) MultiNodeRequested = true when multiple nodes are configured C) not defaulting network_plugin correctly

This allows the downstream defaults to work correctly, likely configuring kindnet for multi node clusters.

TODO:

• [x] Run integration tests locally
• [x] Test a few driver variants (kvm2, docker, hyperkit, hyperv)

[codecov[bot]]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (05337cd) 82.75% compared to head (cdaa5c3) 82.67%.

:exclamation: Current head cdaa5c3 differs from pull request most recent head 72d0402. Consider uploading reports for the commit 72d0402 to get more accurate results

Files	Patch %	Lines
minikube/resource_cluster.go	86.36%	2 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #133 +/- ## ========================================== - Coverage 82.75% 82.67% -0.08% ========================================== Files 12 12 Lines 1003 1016 +13 ========================================== + Hits 830 840 +10 - Misses 148 150 +2 - Partials 25 26 +1 ```

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