Add smarter editor for key iOS files
### Problem to solve
There are certain commonly edited files like PLists, xcodeproj file, and so on that are represented by XML on disk, but are much easier to edit in the XCode UI. We don't necessarily need feature parity with XCode, but we could provide a nicer interface than editing raw XML in the web IDE.
### Target audience
- Sasha, Software Developer, https://design.gitlab.com/research/personas#persona-sasha
### Further details
TBD
### Proposal
TBD
### What does success look like, and how can we measure that?
TBD
### Links / references
issue