DEV: Update linting setup and fix issues (#17345)

Re-lands #16119 and #17298

* Update eslint-config-discourse
* Update linting workflow
* Prettier-ignore stuff
* Update template-lint config
* Auto-fix template issues
* Fix various template issues
  Mostly incorrect attributes and unused templates
* Prettier js files
* Fix template auto-fix regressions
* Small css tweak

Co-authored-by: Peter Wagenet <peter.wagenet@gmail.com>

app/assets/javascripts/admin/addon/controllers/admin-dashboard-reports.js

@@ -12,7 +12,7 @@ export default Controller.extend({
     "filter",
     "siteSettings.dashboard_hidden_reports"
   )
-  filterReports(reports, filter) {
+  filteredReports(reports, filter) {
     if (filter) {
       filter = filter.toLowerCase();
       reports = reports.filter((report) => {