Wt

Related to #13880, where we will allow a more fine-grained approach to the globally configurable alternative.
When requesting a ?request=resource from a bot session, this makes no sense, as they have no session context. This should be handled within the single bot session that requests the page.

Previously, we implemented a way to ensure that the image is rendered out on the server, and served to the client as a data blob, or SVG. The requests themselves are blocked from ever being responded to, so we do not potentially recursively serve pages to bots.
Now we also want to implement a way to override this specific behavior.

Roughly speaking this would be a WImage::setBotAlternative(url) and a WResource::setBotAlternative(url), which both take a URL (equivalent to WLink with LinkType::Url).

This will then be served as the response to the bot INSIDE the original page request.