Add functional code and usage instructions

[Steve-Mcl]

Description

This is the real first code drop for this new repository.

• Add the actual functional code in index.js
  • This is an adaption from the NR flows website, specifically it removes all traces of D3 and jQuery and manages rendering of single and multiple flows and their tabs
• Update README.md with usage examples, acknowledgements and license info Add license
• Update package.json demo script
• Add a demo page (use npm run demo from the command line)
• Rename gitignore to .gitignore to enable it

Related Issue(s)

Checklist

• [x] I have read the contribution guidelines
• [ ] Suitable unit/system level tests have been added and they pass
• [ ] Documentation has been updated
  • [ ] Upgrade instructions
  • [ ] Configuration details
  • [ ] Concepts
• [ ] Changes flowforge.yml?
  • [ ] Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • [ ] Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• [ ] Backport needed? -> add the backport label
• [ ] Includes a DB migration? -> add the area:migration label

[Steve-Mcl]

I think so, that was certainly the intention - let me do a v quick test @joepavitt

[Steve-Mcl]

Joe, updated for esm usage.

Includes updates to readme and built in dev time demos (runnable local via npm run demo)

NOTE: As we may not yet have the API for this as good as it could be, I had set the first version to 0.1.0 and made a reference to the semver rules in the Versioning section in the README.

Please review ASAP.

Screencast from built in demo: