Angular 16

[lukestanley]

I extracted a list of dependent app pages from compile failure:

With the error log by path frequency, the NPM modules for: formly, followed by mermaid, leaflet were top. For our own code src/app/pages/form-builder-page/form-builder-page.component.ts had the most issues, understandably if it's not loaded properly. Followed by our graphql block: src/app/components/block-graphql-builder-box/block-graphql-builder-box.component.ts Then kql-builder page which I'm not familiar with: src/app/pages/kql-builder/kql-builder.component.ts

Here is a rationale for how we might decide what to do: If needed, we might temporarily remove some functionality to make progress with upgrading to Angular 16 if it is minor. Otherwise if it too complex, we might pause work on the upgrade.

[JaimieBlack]

I'll take this on, might need something with write or admin access to assign this to me though :)

[gsambrotta]

PR #425