Restore the directory and file structure of the installed schemas

**Describe the bug**
Since the refactoring the schemas files are not installed to the same location anymore. We want to go back to the previous file organization:

```
.
├── plugInfo.json
└── usdArnold
    └── resources
        ├── generatedSchema.usda
        ├── plugInfo.json
        └── usdArnold
            ├── generatedSchema.usda
            └── schema.usda

```
