Made a mass of accessibility improvements

- Changed default focus styles
- Updated dropdowns with keyboard navigation
- Updated modals with esc exiting
- Added accessibility attirbutes where needed
- Made many more elements focusable
- Updated hover effects of many items to also apply when focused within

Related to #1320 and #1198

resources/views/components/expand-toggle.blade.php

@@ -3,13 +3,13 @@ $target - CSS selector of items to expand
 $key - Unique key for checking existing stored state.
 --}}
 <?php $isOpen = setting()->getForCurrentUser('section_expansion#'. $key); ?>
-<a expand-toggle="{{ $target }}"
+<button type="button" expand-toggle="{{ $target }}"
    expand-toggle-update-endpoint="{{ url('/settings/users/'. $currentUser->id .'/update-expansion-preference/' . $key) }}"
    expand-toggle-is-open="{{ $isOpen ? 'yes' : 'no' }}"
    class="text-muted icon-list-item text-primary">
     <span>@icon('expand-text')</span>
     <span>{{ trans('common.toggle_details') }}</span>
-</a>
+</button>
 @if($isOpen)
     @push('head')
         <style>