Registry Viewer Source Code Documentation

### Background:
Currently there is no documentation for the Registry Viewer.

### Work:
Add comments using the [TSDoc](https://tsdoc.org/) standard and then use [TypeDoc](https://typedoc.org/) to convert comments in TypeScript source code into rendered HTML documentation or a JSON model.

### Related Issue:
https://github.com/devfile/api/issues/382 (Registry Viewer)
