media assets: redesign show page.

Redesign the media assets show page to:

* Include sidebar with AI tags and image metadata.
* Include next and previous image buttons.
* Make the image use 100% of the available screen space and to scroll with the window.

app/components/media_asset_component.rb

@@ -2,12 +2,19 @@
 
 # A component for showing a full-sized image or video for a media asset.
 class MediaAssetComponent < ApplicationComponent
-  attr_reader :media_asset
+  attr_reader :media_asset, :current_user, :outer_classes, :inner_classes, :dynamic_height
 
   delegate :image_width, :image_height, :variant, :is_image?, :is_video?, :is_ugoira?, :is_flash?, to: :media_asset
 
-  def initialize(media_asset:)
+  renders_one :header
+  renders_one :footer
+
+  def initialize(media_asset:, current_user:, outer_classes: "", inner_classes: "", dynamic_height: false)
     super
     @media_asset = media_asset
+    @current_user = current_user
+    @outer_classes = outer_classes
+    @inner_classes = inner_classes
+    @dynamic_height = dynamic_height
   end
 end