Use Angular 14 Typed Forms

[jamesrwelch]

Angular 14 introduces Typed Forms: https://angular.io/guide/typed-forms
If we were to use these in our code we'd get better type-checking and hopefully better code quality.
The current code uses the default UntypedForm in the few places where Forms are actually defined - these need converting to proper Typed versions, and there are probably other places in the code where explicit Form definitions could be introduced.