Show previeable content in the editor

Embedded PDF previewing isnt' reliable (not working in Safari with active storage). Instead
let's align the editor with Active Storage previews and support pdf previews

Dockerfile

@@ -47,7 +47,7 @@ FROM base
 
 # Install packages needed for deployment
 RUN apt-get update -qq && \
-    apt-get install --no-install-recommends -y curl libsqlite3-0 libvips && \
+    apt-get install --no-install-recommends -y curl libsqlite3-0 libvips build-essential ffmpeg groff libreoffice-writer libreoffice-impress libreoffice-calc mupdf-tools  && \
     rm -rf /var/lib/apt/lists /var/cache/apt/archives
 
 # Copy built artifacts: gems, application