Updated README's

[rtwksai]

Fixes #2161

Short description of what this resolves:

Changes proposed in this pull request:

• Updated Node version in README.md
• Updated links to README in frontend/README.md
• Updated links to README in backendend/README.md

Checklist

• [x] I have read the Contribution & Best practices Guide.
• [x] My branch is up-to-date with the Upstream development branch.
• [x] The acceptance, integration, unit tests and linter pass locally with my changes
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] I have added necessary documentation (if appropriate)