NFSAAS-1708 add ANF CLI extension to index

[leonardbf]

Plus correct some help validation errors

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This checklist is used to make sure that common guidelines for a pull request are followed.

General Guidelines

• Have you run ./scripts/ci/test_static.sh locally? (pip install pylint flake8 required)
• Have you run python scripts/ci/test_index.py -q locally?

For new extensions:

• My extension description/summary conforms to the Extension Summary Guidelines.