docs: deprecate read only assets (#4226)

* chore: add deprecation notice in docs

* feat: link to library documentation

---------

Co-authored-by: Jason Rasmussen <jrasm91@gmail.com>

docs/docs/features/read-only-gallery.md

@@ -1,22 +1,16 @@
-# Read-only Gallery [Experimental]
-
-## Overview
-
-This feature enables users to use an existing gallery without uploading the assets to Immich.
-
-Upon syncing the file information, it will be read by Immich to generate supported files.
+# Read-only Gallery [Deprecated]
 
 :::caution
 
-This feature is still in an experimental stage. And this is an initial implementation and will receive improvements in the future.
+This feature is being deprecated in favor of [Libraries](/docs/features/libraries.md).
 
-The current limitations of this feature are:
+:::
 
-- Assets are not automatically synced and must instead be manually synced with the CLI tool.
-- Only new files that are added to the gallery will be detected.
-- Deleted and moved files will not be detected.
+## Overview
 
-:::
+This feature enables users to use an existing gallery without uploading the assets to Immich.
+
+Upon syncing the file information, it will be read by Immich to generate supported files.
 
 ## Usage