My Jetpack: Add react-router for route handling

[renatoagds]

Implement the route system inside My Jetpack, with a hook to block direct navigation to the component.

Changes proposed in this Pull Request:

• Setup HashRouter and Routes.
• Include useRouteBlocker that blocks direct route access for some component, it will only be allowed if coming from other router.

Jetpack product discussion

p1643660572899069-slack-C02TQF5VAJD

Does this pull request change what data or activity we track or use?

No.

Testing instructions:

• Goes into MyJetpackScreen component
• Insert a Link component from react-router-dom any place, and set the to for /new route.
• Build My Jetpack (jetpack build packages/my-jetpack).
• Navigate to My Jetpack.
• Click in the Link.
• It should load the New screen.
• Go back and try to go forward.
• It will redirect you back to the My Jetpack screen.
• Click on the link again.
• Refresh the page.
• It will redirect you back to the My Jetpack screen.

Demo

route-blocker-example.mp4

[matticbot]

Caution: This PR has changes that must be merged to WordPress.com
Hello renatoagds! These changes need to be synced to WordPress.com - If you 're an a11n, please commandeer and confirm D74125-code works as expected before merging this PR. Once this PR is merged, please commit the changes to WP.com. Thank you!
This revision will be updated with each commit to this PR

[github-actions]

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[oskosk]

Tests exactly as described 🚢

[github-actions]

Great news! One last step: head over to your WordPress.com diff, D74125-code, and commit it.
Once you've done so, come back to this PR and add a comment with your changeset ID.

Thank you!

[anomiex]

r239427-wpcom