Docs: Tidy/Enhance README.md ready for Open Source

[nelsonic]

As noted in https://github.com/quantum-wealth/docs/issues/46 we want to Open Source as much non "secret sauce" code/components as possible to invite contribution from the coding community.
Sealed Secrets are a great candidate for Open Source because they are generally useful to most teams/projects/companies and not at all specific to us.
With this in mind, we need to review the README.md of this project and tidy+enhance it for public consumption to answer as many common "onboarding" questions as possible and streamline the process of running/deploying the UI.

Todo

• Review the README.md with a beginner's mind 🔰
• Answer any questions we have while reading it.
  • Why?
  • What?
  • Who?
  • How?
• Run the app on localhost as fill-in any gaps in the setup instructions - this is the baseline for contribution.
• Describe how to deploy to our (internal) infra
• Show how to deploy to alternative cloud and/or on-prem
• Describe how people can contribute if appropriate

Bonus Level

• Add GitHub CI to test the code.
• Add necessary tests to gain confidence that nothing will break when people contribute.
• Add in-line comments as needed to clarify any code (not much)
• Refactor as needed to make functions testable (don't think much is necessary)

[nelsonic]

Add link to: https://youtu.be/E0F4usFauvc