Report UX improvements (#314)

* Prepare pages payload for data tables.

* Ensure each rule has actionable pill text for index.

* Pass pill text to each page’s results.

* Use data table.

* Make url link to actual page (you can see actionable modal if you click on pills).

* Pills wip.

* Improve status column handling.

* Make item url in model footer clickable.

* Fix little header styling.

* Fix right margin on visit link.

* Switch from yellow-dark to orange, looks nicer.

* Summary card idea.

* Fix green, and make score percentage match bar.

* Ensure warnings get sorted between failures and successes in data table.

* Show explicit `Visit` vs `Edit` action links.

* Show more info on reports index table.

* Actionable Pages stat (wip).

* Cache actionable pages count at top level of generated report.

* Add test coverage.

* Wire up actual pages actionable (showing N/A for old reports only).

* Match status color on reports index to site score & progress bar color on report show view.

* Fix initial show page load performance.

* Actually return data when asked for it.

* Only output pages and column data when pages are available on instance already.

* Always set `loading` to true by default.

* Use computed `sortablePages` here too.

* Pagination 🥵🥵🥵

* Don’t need this anymore.

* Extract this stuff out to its own controller.

* Fix var reference.

* Cleanup.

* Fix regression during generation.

* Fix modal link bug, since renaming column.

* Build.

* Mark dark mode less bad.

* 404 for non-existing reports.

* Build.

* Fix dark mode here too.

* Wrap groups with `@if`.