Network policy stats

What does this MR do?

This MR adds Network Policy section to the Threat Monitoring page. Stats are based on per namespace prometheus metrics.

Frontend changes:

• Refactored WAF components to be reusable.
• Introduced ThreatMonitoringSection component.
• Added network policy related changes to the store, behind the network_policy_ui feature flag.
• Disabled callout at the top as requested in the issue.
• Make the x-axis render the requested range, rather the the range of the returned data (See #14707 (comment 301880401)).
• Change the 7 day interval to a day, for a less noisy graph (see #14707 (comment 301077240)).

Notes:

• Changed documentation path to the new docs page as requested in the issue. This doc is empty will create content for it in a separate MR.
• Empty states are being re-designed so I only did minimal changes to those. Will create a separate MR for the new empty states.

Related to #32365 (closed). Backend part is in !25939 (merged)

Screenshots

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Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done