refactor: upgrade React Router to v6

[damianstasik]

New Pull Request Checklist

• [x] I am not disclosing a vulnerability.
• [x] I am creating this PR in reference to an issue.

Issue Description

Related issue: #1902

Approach

TODOs before merging

• [ ] Add tests
• [ ] Add changes to documentation (guides, repository pages, in-code descriptions)
• [x] A changelog entry is created automatically using the pull request title (do not manually add a changelog entry)

[parse-github-assistant[bot]]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[mtrezza]

Damian, would you be available for a chat on Slack?

[damianstasik]

@mtrezza yes, sure! You can reach me at <REMOVED>

[mtrezza]

@visualfanatic What is the state of this PR? Are you actively working on it?

[damianstasik]

@mtrezza I checked changes on alpha since my last update here and it looks like I don't have to adjust. Now I am going through each file making sure everything works as expected, and then I think it could be ready to be reviewed.

[mtrezza]

Amazing, this will be a great merge!

[damianstasik]

@mtrezza what should we do about failing CI due to minimum Node version required by React Router 6?

[damianstasik]

@mtrezza I saw that there was an issue to remove Node 12 support, so I quickly did that to unblock this PR with updated router: https://github.com/parse-community/parse-dashboard/pull/2277

[mtrezza]

@damianstasik Is his ready for review? If so, please request from dashboard-review team.

[parseplatformorg]

🎉 This change has been released in version 5.0.0-alpha.4

[parseplatformorg]

🎉 This change has been released in version 5.0.0-beta.1

[parseplatformorg]

🎉 This change has been released in version 5.0.0