[yurt-tunnel]improve the usage of certificates

[rambohe-ch]

What would you like to be added:
There are no restrictions on the use of yurt-tunnel certificates, the code reference is:
https://github.com/openyurtio/openyurt/blob/master/pkg/yurttunnel/pki/certmanager/certmanager.go#L147-L149

		Usages: []certificates.KeyUsage{
			certificates.UsageAny,
		},

we need to specify the usage of certificates of yurt-tunnel components clearly.

Why is this needed:
In order to reduce the risk of certificate safety, It's not recommended to define any usage for certificates.

others
/kind feature

[ghost]

It seems that the issue is not assigned to anyone yet. I would assign it to myself now, if there is any problem, please let me know.

[ghost]

/assign

[rambohe-ch]

@joker-joker-joker Very appreciate you for taking over this feature.

/assign @joker-joker-joker

[ghost]

After I modify the code, according to the https://github.com/khalid-jobs/openyurt/blob/master/docs/tutorial/yurt-e2e-test.md, if I pass ./_output/bin/darwin/amd64/yurt-e2e-test --kubeconfig=/root/.kube/config --report-dir=./, does it mean that there is no problem with my modification? And do I need to convert the k8s cluster to openyurt cluster before I run test command ?
Can I just use one machine to run the test? For example I use kind to start a cluster(a master and a node).

[ghost]

/assign

[ghost]

It seems that the openyurt's action does not have a auto e2e(start a new cluster using the latest code) like kubeedge? https://github.com/kubeedge/kubeedge/runs/3573841016?check_suite_focus=true. I think this is very helpful for developer to test.

[rambohe-ch]

After I modify the code, according to the https://github.com/khalid-jobs/openyurt/blob/master/docs/tutorial/yurt-e2e-test.md, if I pass ./_output/bin/darwin/amd64/yurt-e2e-test --kubeconfig=/root/.kube/config --report-dir=./, does it mean that there is no problem with my modification? And do I need to convert the k8s cluster to openyurt cluster before I run test command ?
Can I just use one machine to run the test? For example I use kind to start a cluster(a master and a node).

@ke-jobs Now we need to prepare a openyurt cluster and check the logs of openyurt components(like yurthub or yurt-tunnel) to check that components work normally or not.

now github actions for OpenYurt only check go test and go imports and go. build, it's not enough. we need to append some github action for e2e. would you like to take over this action?