Add cncf webinar slides for v1.33

[npolshakova]

What type of PR is this:

/kind documentation

What this PR does / why we need it:

Adds slides to v1.33 release directory as a reference for the webinar.

The presentation is a release artifact so it may be useful to start uploading them to the release-1.33 folder in the k/sig-release repo. Open to suggestions if we want this to live somewhere else!

Which issue(s) this PR fixes:

None

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[wendy-ha18]

@npolshakova I love this idea even I haven't seen any release lead sharing this webinar slides on the previous release folders. But I personally would love it be there as a resource of the release and let's everyone review or reference about it in the future.

A small note, not sure why but I couldn't see your slides from the commit, just the name of it. However just note that the name Kubernetes v1.33 Release Webinar.pdf should be changed to conventional naming without space in between.