New local setup (hybrid solution)

[allinox]

Description

This PR sets up a new way of running the frontend locally, without also running the many dependencies locally as well. Description and steps for setup has been added to the readme

Changes made:

• Added new launch setup for the AT22-hybrid method
• Added logic to index file to make sure the local react code is used by the BFF
• Added description/steps to readme

Related Issue(s)

• 797

Verification

• [ ] Your code builds clean without any errors or warnings
• [ ] Manual testing done (required)
• [ ] Relevant automated test added (if you find this hard, leave it and we'll help out)
• [ ] All tests run green

Documentation

• [ ] User documentation is updated with a separate linked PR in altinn-studio-docs. (if applicable)

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
50.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud