Image uploads disabled

[Nutomic]

1.0 has a new config option image_upload_disabled. This is enabled on voyager.lemmy.ml. Still lemmy-ui lets you upload images in the create post screen, and doesnt show any error message when that fails.

Ideally image upload should be hidden in this case, but its tricky because the server config is not available to the client.

[dessalines]

All off these settings need to be moved to the local_site table. It should be possible to update them live, and they should come back with GetSite.

Really the only things that should be in lemmy.hjson, are wiring related and things necessary for server startup. Everything else should be in the DB.