Add version picker to side menu

[DuskoPeric]

PR Checklist

Please check if your PR fulfills the following requirements:

• [ x] The commit message follows our guidelines: https://github.com/ngrx/platform/blob/main/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Documentation has been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

The new website doesn't have version picker.

Closes #4975

What is the new behavior?

The new website has version picker.

Does this PR introduce a breaking change?

[ ] Yes
[x ] No

[netlify]

✅ Deploy Preview for ngrx-io canceled.

Name	Link
🔨 Latest commit	553f5f4
🔍 Latest deploy log	https://app.netlify.com/projects/ngrx-io/deploys/69345317a2cec00008cc90c5

[netlify]

✅ Deploy Preview for ngrx-site-v19 ready!

Name	Link
🔨 Latest commit	553f5f4
🔍 Latest deploy log	https://app.netlify.com/projects/ngrx-site-v19/deploys/69345317e122870007127885
😎 Deploy Preview	https://deploy-preview-5040--ngrx-site-v19.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 project configuration.

[timdeschryver]

Thanks @DuskoPeric !