Add support for React router v7

[djhi]

Problem

react-router v7 is out

Solution

Follow #10437 and #10439

• Add support for React router v7

• react-admin packages will still use v6 in their devDependencies to ensure we don't use v7 only features inadvertently.

• The tutorial and e-commerce demo will use v7 so that we have an easy way to test v7

How To Test

Works with v6

• build the RA packages locally from this branch
• create a new react-admin app: npm init react-admin react-admin-router
• add the MUI deps: npm add react-router@6 react-router-dom@6
• copy the built packages to the react-admin-router/node_modules directory
• Run the app & check your lock file

Works with v7

• change the previous app MUI dependencies to ^7.0.0
• npm install
• Run the app & check your lock file

Additional Checks

• The PR targets master for a bugfix, or next for a feature

[djhi]

This used to be only available from react-router-dom so it "proves" we use v7

[smeng9]

I think a non breaking change way to migrate to react-router v7 is always use react-router-dom package inside react-admin. It is a re-export of react-router https://reactrouter.com/start/changelog#package-restructuring

Then people using react-router v6 won't be affected by such things like import { Link } from 'react-router(v6)'; that does not exist

[smeng9]

Oh I see it is for demo project, not package itself. I misunderstood the previous message.