Fullscreen MediaViewer refactor

- Moved media related logic into notedeck instead of the ui crate,
  since they pertain to Images/ImageCache based systems

- Made RenderableMedia owned to make it less of a nightmware
  to work with and the perf should be negligible

- Added a ImageMetadata cache to Images. This is referenced
  whenever we encounter an image so we don't have to
  redo the work all of the time

- Relpaced our ad-hoc, hand(vibe?)-coded panning and zoom logic
  with the Scene widget, which is explicitly designed for
  this use case

- Extracted and detangle fullscreen media rendering from inside of note
  rendering.  We instead let the application decide what action they
  want to perform when note media is clicked on.

- We add an on_view_media action to MediaAction for the application to
  handle. The Columns app uses this toggle a FullscreenMedia app
  option bits whenever we get a MediaAction::ViewMedis(urls).

Signed-off-by: William Casarin <jb55@jb55.com>

crates/notedeck_columns/src/view_state.rs

@@ -6,8 +6,12 @@ use crate::deck_state::DeckState;
 use crate::login_manager::AcquireKeyState;
 use crate::ui::search::SearchQueryState;
 use enostr::ProfileState;
+use notedeck_ui::media::MediaViewerState;
 
 /// Various state for views
+///
+/// TODO(jb55): we likely want to encapsulate these better,
+/// or at least document where they are used
 #[derive(Default)]
 pub struct ViewState {
     pub login: AcquireKeyState,
@@ -16,6 +20,11 @@ pub struct ViewState {
     pub id_string_map: HashMap<egui::Id, String>,
     pub searches: HashMap<egui::Id, SearchQueryState>,
     pub pubkey_to_profile_state: HashMap<Pubkey, ProfileState>,
+
+    /// Keeps track of what urls we are actively viewing in the
+    /// fullscreen media viewier, as well as any other state we want to
+    /// keep track of
+    pub media_viewer: MediaViewerState,
 }
 
 impl ViewState {