[calico] don't enable ipip encapsulation by default and use vxlan in CI (#8434)

* [calico] make vxlan encapsulation the default

* don't enable ipip encapsulation by default
* set calico_network_backend by default to vxlan
* update sample inventory and documentation

* [CI] pin default calico parameters for upgrade tests to ensure proper upgrade

* [CI] improve netchecker connectivity testing

* [CI] show logs for tests

* [calico] tweak task name

* [CI] Don't run the provisioner from vagrant since we run it in testcases_run.sh

* [CI] move kube-router tests to vagrant to avoid network connectivity issues during netchecker check

* service proxy mode still fails connectivity tests so keeping it manual mode

* [kube-router] account for containerd use-case