Validate GUI yaml

**Is your feature request related to a problem? Please describe.**
As a user, it might be unclear how to make the gui yaml.

**Describe the solution you'd like**
It would be nice for the view repo to have a way to validate the yaml and then give clear feedback if something is wrong before booting the whole thing up and crashing. Maybe pydantic? I have suspensions that pydantic would not have the flexibility for something like the yaml since ideally you can use different widgets for different devices but worth looking into. Also would be useful for voxel

**Acceptance Criteria**
- [ ] validation of gui yaml
- [ ] gives warnings before booting up and crashing