Topic relevance validator

[rkritika1508]

Is your feature request related to a problem? Please describe.
Topic relevance validator is one of the newer set of validators we are working on.

• Add validator code
• Add APIs to manage topic relevance validator configuration
• Update documentation
• Add API documentation
• Add unit tests

Describe the solution you'd like
A clear and concise description of what you want to happen.

Describe alternatives you've considered
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Additional context
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