Report UX and performance improvements

[jesseleite]

Users have mentioned that it's really hard to work through a report with thousands of pages, because actionable items get buried way down the report. Also if enough vue components are registered, the report view starts to chug.

This PR gives the whole SEO reporting section a facelift, puts more of a priority on showing actionable items first, and also solves the above-mentioned performance problems by paginating results.

BEFORE:

Old reports index...

Old report details view...

AFTER:

New reports index 💅

New report details view 💅💅💅

---

TODO:

• Report generation
  • Cache actionable pages count at top level of generated report
    • Add test coverage
• Reports listing
  • Add column headers
  • Add actionable pages column
  • Add pages crawled column
  • Fix status icon color to match site score status color on report show page
  • Fix dark mode
• Report show page
  • Unify summary cards into one summary card
  • Make pages list a proper data-table
  • Add 'Actionable' column with pills showing what needs updating
    • Title
    • Description
    • Url
  • Allow sorting by column
    • Sort by status
      • Actionable items first by default
        • Failures, then warnings, then passing pages at bottom
    • Sort by url
  • Data table pagination for large data sets
  • Make url in actionable modal footer clickable
  • Add entry edit buttons to each row
  • Add entry edit buttons to actionable modals
  • Fix green colour styles
  • Improve warning colour styles
  • Fix dark mode