doc(dns-visibility): add dns-visibility documentation

[rksharma95]

Purpose of PR?:
add documentation for dns-visiblity with an example showcasing dns visibility logs for a egress network event at pod level.

Does this PR introduce a breaking change?

If the changes in this PR are manually verified, list down the scenarios covered::

Additional information for reviewer? :
Mention if this PR is part of any design or a continuation of previous PRs

Checklist:

• Bug fix. Fixes #
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• PR Title follows the convention of <type>(<scope>): <subject>
• Commit has unit tests
• Commit has integration tests