Update documentation to remove duplication and broken example usage

[FeargusOG]

Updated documentation:

• Follow the DRY principle.
• Implement a separation of concerns so that the:
  • The README.md contains information related to developing and building the provider.
  • The CONTRIBUTING.md contains information related to contributing to the provider.
  • The docs/index.md contains information related to using the provider to manage Aria Operations for Applications resources.
• Fix the example usage in the docs/index.md file.