Corpus Management - v2 Empty state

Original designs called for a simple empty state as seen below:

Before

To maintain consistency with other pages within the Secure product area, a new version has been proposed. Changes include the following items:

• Remove the page title, table header, etc.
• Add an illustration, title, and New corpus button in the empty state
• Update the empty state text to: A corpus is used by fuzz testing to improve coverage. Corpus files can be manually created or auto-generated. Learn more.
  • Note: The "Learn more" text should link to: https://docs.gitlab.com/ee/user/application_security/coverage_fuzzing/#corpus-registry

After

Figma: https://www.figma.com/file/eSIeuIPKFwEDs4X9ky2O5E/Corpus-Registry?node-id=2169%3A17823