documentation

[lsat12357]

List of potential tweaks:

• RAIS_IIIFURL is still lurking in a few places in the wiki (deprecated in v4)
• Docker is discussed on the Installation page, but then again on its own child page, and again (a bit) in the Development guide. The content on the Docker page is probably more current, as it doesn't refer to RAIS_IIIFURL. Potentially merge all the content to the child page and just link to it?
• On the docker demo page, it might be helpful to note that images added to docker/images don't appear until the container is restarted.
• Development guide has a link to a wiki page that doesn't exist: Setup