Network policy management editor

What does this MR do?

This MR adds policy management drawer to the Policies tab of the Threat Monitoring page. This drawer shows policy's yaml manifest and allows editing via a simple wrapper component based on the monaco editor. Editing is temporary disabled for the upcoming release.

This MR is a part of ongoing work for the new Policy Management UI (&3328 (closed))

Screenshots

Without Changes	With Changes

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

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team