Add prerequisite when installing via helm

[ArangoGutierrez]

Currently by "simply" following the instructions users face with:

❯    helm install kserve oci://ghcr.io/kserve/charts/kserve --version v0.13.0

Pulled: ghcr.io/kserve/charts/kserve:v0.13.0
Digest: sha256:84ec987a507fd494e9e1e4fb8110c56594fa37609cff6bd1d6eb4b5b84386aee
Error: INSTALLATION FAILED: unable to build kubernetes objects from release manifest: [resource mapping not found for name: "serving-cert" namespace: "default" from "": no matches for kind "Certificate" in version "cert-manager.io/v1"
ensure CRDs are installed first, resource mapping not found for name: "modelmesh-webhook-server-cert" namespace: "default" from "": no matches for kind "Certificate" in version "cert-manager.io/v1"
ensure CRDs are installed first, resource mapping not found for name: "selfsigned-issuer" namespace: "default" from "": no matches for kind "Issuer" in version "cert-manager.io/v1"

[netlify[bot]]

✅ Deploy Preview for elastic-nobel-0aef7a ready!

Name	Link
🔨 Latest commit	36fea731891afe11ca8a29fb24b08581cd7e266c
🔍 Latest deploy log	https://app.netlify.com/sites/elastic-nobel-0aef7a/deploys/66841ddf2359ff000800547d
😎 Deploy Preview	https://deploy-preview-379--elastic-nobel-0aef7a.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.

[ArangoGutierrez]

PING @alexagriffith @theofpa

[oss-prow-bot[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: ArangoGutierrez, terrytangyuan Once this PR has been reviewed and has the lgtm label, please assign yuzisun for approval by writing /assign @yuzisun in a comment. For more information see:The Kubernetes Code Review Process.

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

Needs approval from an approver in each of these files: - **[OWNERS](https://github.com/kserve/website/blob/main/OWNERS)** Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[terrytangyuan]

/lgtm /assign @yuzisun

[ArangoGutierrez]

/close