Move jquery-specific functions to `jq/`
Factor "html/e_type_admin.media"

Include "html/e_type_admin.media", not "html/e_type_admin.jnj.media" in
"html/site_admin.jnj.media" (avoid javascript errors resulting from
different DOMs)
Use `$GTW.show_message`, not `console.error`

Not every browser supports `console`