Resolve "Copy repo ELLA future frontend in react into repo"

Description

Restructuring:

• Moved all source code (except scaffolding) from https://gitlab.com/alleles/ella-frontend (81b7ea6899a257554195220d4e5f8496ecab3c77)
• Moved all BDD tests
• Moved old frontend/ folder to frontend-legacy/

New files:

• Created two new Dockerfiles (Dockerfile.frontend and Dockerfile.bdd, old Dockerfile.frontend moved to Dockerfile.frontend-legacy)
• Added new compose file (docker-compose-bdd.yaml) to run BDD tests in a similar fashion as docker-compose-e2e.yaml
• Devcontainer files for new frontend and bdd - old devcontainer still available. All three can run in different windows simultaneously.

Modifications:

• compose files now include new frontend
• nginx updated so that the new frontend is available at http://react.localhost:8080
• pre-commit config updated with eslint for new frontend
• CI running bdd test
• CI running jest on new frontend

Notes to review (code/docs/QA)

Only a single bdd test is running in the CI - lots of failing tests. This needs to be resolved in a different MR.

Related issues

Closes #2294 (closed)