Remove standard from feature-set names

[tssurya]

We were calling our feature sets as StandardCoreFeatures and StandardExtendedFeatures. This was in anticipation of Standard and experimental channels which is not something we have strongly started to use.

So having standard and extended as way forward is easier than having standard.core, standard.extended and experimental.core, experimental.extended sets.

/assign @astoycos In relation to review comment: https://github.com/kubernetes-sigs/network-policy-api/pull/138#discussion_r1358742954

So we will go with standard channel = core features experimental channel = extended features

[k8s-ci-robot]

Skipping CI for Draft Pull Request. If you want CI signal for your change, please convert it to an actual PR. You can still manually trigger a test run with /test all

[netlify[bot]]

✅ Deploy Preview for kubernetes-sigs-network-policy-api ready!

Name	Link
🔨 Latest commit	028046057153c705c7dc80c53a174523ba03ae2a
🔍 Latest deploy log	https://app.netlify.com/sites/kubernetes-sigs-network-policy-api/deploys/652bfffdcc8adc00095277b7
😎 Deploy Preview	https://deploy-preview-155--kubernetes-sigs-network-policy-api.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: astoycos, tssurya

The full list of commands accepted by this bot can be found here.

The pull request process is described here

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