Improve navigation by pressing tab for accessibility

src/app/app.component.html

src/app/core/components/feedback/feedback.component.scss

src/app/core/components/main/header/header.component.html

src/app/core/components/main/main.component.html

src/app/core/components/main/main.component.scss

src/app/core/components/main/main.component.ts

...pi/resources-queryable/resources-queryable.component.html

...pi/resources-queryable/resources-queryable.component.scss

...l/components/dataset-detail/dataset-detail.component.html

...ource-download-item/resource-download-item.component.html

...ource-download-item/resource-download-item.component.scss

...etail/components/dataset-info/dataset-info.component.html

...nts/dataset-info/info-summary/info-summary.component.html

...l/components/dataset-reuses/dataset-reuses.component.html

...ts/filter-list/filter-detail/filter-detail.component.html

...ts/filter-list/filter-detail/filter-detail.component.scss

...atasets/components/filter-list/filter-list.component.html

...ents/results/result-dataset/result-dataset.component.html

...esults/results-tab-scope/results-tab-scope.component.html

...esults/results-tab-scope/results-tab-scope.component.scss