Add CSP headers to the karma run

[rajsite]

Pull Request

Add docs for Content Security Policy configuration and run tests with a defined Content Security Policy.

🤨 Rationale

End goal is to be aware / prevent regressions to CSP safety (i.e. prevent adoption of a library that requires eval usage, etc).

👩‍💻 Implementation

Created security policies for the karma test runners aligned with OWASP Basic non-Strict CSP Policy with additions needed for nimble / specific test runners.

🧪 Testing

Rely on CI.

✅ Checklist

• I have updated the project documentation to reflect my changes or determined no changes are needed.
  • README docs added to nimble components. Didn't really seem worth linking to it from all the wrappers so just captured it on components. Each of the frameworks has their own docs, i.e. Angular and Blazor and didn't seem like something we need to duplicate and merge in.