Restore the directory and file structure of the installed schemas

[cpichard]

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

[autodesk-oss-arnold-bot]

Issue synced internally to ARNOLD-14024