automate the process of generate tls certs in vpa-up.sh via initcontainer

[yf4n]

What type of PR is this?

/kind feature

What this PR does / why we need it:

When deploy vpa with vpa-up.sh, script will generate tls certs on host. Different openssl version on host may be cause tls certs generate failed, then admission controller pod create failed with error: MountVolume.SetUp failed for volume "tls-certs" : secret "vpa-tls-certs" not found.

Which issue(s) this PR fixes:

Fixes #5615 #6126

Special notes for your reviewer:

generate tls certs via initcontainer, save it to emptydir volumes.

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

NONE

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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