Adds demo time sample

[Adam-it]

• New sample
• Bug fix/update
• Related issues: fixes #X, partially #Y, mentioned in #Z

What's in this Pull Request?

The PR adds a new sample Demo Time which allows you to add presentation mode to any page of any site and treat sections on pages as there would be slides.
This web part is a total hack that interacts with pages DOM which is not recommended.
This web part is a kind of a POC created for the SharePoint Hackathon

Node Version

Node version used:

v18.20.3

Checklist

• My pull request affects only ONE sample.
• My sample builds without any warnings
• I have updated the README.md file's Version history. For new samples, created a new README.md file matching this template
• My README.md has at least one static high-resolution screenshot (i.e. not a GIF) located in the assets folder.
• My README.md contains complete setup instructions, including pre-requisites and permissions required
• My solution includes a .nvmrc file indicating the version of Node.js

[github-actions]

Sample PR validation for #5423

⚠️ Validation status: warnings

We automatically validate all pull requests against our contribution guidance to ensure that all samples provide a consistent experience to our community.

In order to merge this PR in a timely manner, the following criteria must be met:

Validation	Status
Pull request affects only one folder	⚠️ Warning
Sample folder name follows naming convention	✅ Succeeded
README.md contains visitor stat image	✅ Succeeded
Sample requires a .nvmrc file	✅ Succeeded
Sample requires a README.md	✅ Succeeded
Sample requires a screenshot .png in assets folder	✅ Succeeded
No .sppkg file	✅ Succeeded
No node_modules folder	✅ Succeeded
No lib folder	✅ Succeeded

@Adam-it please address the above issues and push new changes to this branch.
For more information, see the contribution guidance.

[Adam-it]

the changes outside of the sample folder were done by the gh action
e28f5ab

[hugoabernier]

the changes outside of the sample folder were done by the gh action e28f5ab

Good catch. I'll add logic to ignore those changes.

[github-actions]

Sample PR validation for #5423

⚠️ Validation status: warnings

We automatically validate all pull requests against our contribution guidance to ensure that all samples provide a consistent experience to our community.

In order to merge this PR in a timely manner, the following criteria must be met:

Validation	Status
Pull request affects only one folder	⚠️ Warning
Sample folder name follows naming convention	✅ Succeeded
README.md contains visitor stat image	✅ Succeeded
Sample requires a .nvmrc file	✅ Succeeded
Sample requires a README.md	✅ Succeeded
Sample requires a screenshot .png in assets folder	✅ Succeeded
No .sppkg file	✅ Succeeded
No node_modules folder	✅ Succeeded
No lib folder	✅ Succeeded

@Adam-it please address the above issues and push new changes to this branch.
For more information, see the contribution guidance.

[hugoabernier]

Thank you @Adam-it for your sample! Always appreciated!

We'd love to have your sample featured in one of our future community calls.

If haven't done so yet, and you'd be interested on showing this great sample in a public community call, please fill in following form and we'll get you scheduled - aka.ms/community/request/demo

Thank you for sharing your sample with others - you rock! 👏🥇👩‍💻