npep-285: Combine ANP and BANP

[npinaeva]

Current version doesn't suggest a specific API, but outlines different options. After this EP gets some feedback, it will be updated with the winning options.
tracking issue #285

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[k8s-ci-robot]

@npinaeva: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-network-policy-api-verify	bb5519a	link	true	/test pull-network-policy-api-verify

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