Move CONTRIBUTING.rst to the monorepo root.

[chalmerlowe]

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Summary of the feature request

Consolidate package level CONTRIBUTING.rst file contents into a single global file at the monorepo root level to expand upon/enhance the existing file.

Remove package level CONTRIBUTING.rst files from the packages, unless there is a package specific nuance that must be included in a package level file.

Ensure any package level files have a link to the global file.

Desired code experience

N/A

Expected results

N/A

API client name and version

No response

Use case

Removing this file from each package decreases the overall maintenance burden that is currently present.

Additional context

N/A