feat: add benchmark and skipping features example

[crandles]

What type of PR is this?

/kind documentation

What this PR does / why we need it:

This adds an example of skipping the features package and how to run a benchmark using the testenv client.

Which issue(s) this PR fixes:

Fixes #268

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., Usage docs, etc.:

See included README

[k8s-ci-robot]

Hi @crandles. Thanks for your PR.

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: crandles, vladimirvivien

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/kubernetes-sigs/e2e-framework/blob/main/OWNERS)~~ [vladimirvivien] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[vladimirvivien]

@cpanato @harshanarayana PTAL