Manual: watchlist titles that aren't in the library yet #63

Silo now keeps movies and series on a profile's watchlist before the library
has them. The manual's watchlist, requests and poster badge pages don't
describe this. Server change: Silo-Server/silo-server#1711. It is merged.

Pages to update:

• Watchlist. The watchlist page has two tabs, "In your library" and "Not in
  your library yet". The second lists titles added from Discover that the
  library doesn't have. They can't be played. When one arrives, it moves to
  "In your library", keeping the date it was added. A title that TMDB lists
  twice shows "TMDB lists it twice", and one TMDB no longer lists shows "No longer
  listed on TMDB". Both have a "Find it" link to search for the title again. Keeping
  these titles needs requests enabled on the server. While requests are off,
  existing entries are kept but can't be listed, added or removed.
• Discover. A title page and its poster cards have an "Add to Watchlist"
  button, which shows "On Watchlist" once added.
• Requests, for users. By default, adding a title the library doesn't have
  to the watchlist also requests it, or follows someone else's request for it,
  and the user is notified when it arrives. A profile can turn this off in
  Settings › Requests with "Request titles I add to my watchlist". Removing the
  title from the watchlist cancels a request the watchlist made, as long as it
  hasn't been sent to a download server yet.
• Requests, for admins. Admin Settings › Requests has "Request titles added
  to a watchlist" (on by default). Turn it off to stop watchlist adds from
  making requests; entries are still kept. The request queue marks these
  requests "via watchlist". Request limits, approval and routing apply as for
  any other request.
• Poster badges. A new "Request Status" badge (top-left, on by default)
  shows a watchlist title's request status on its poster: "Downloading 43%",
  "Out Dec 18", "Approved", "Awaiting approval", "Not requested", "Needs
  attention" or "Not on TMDB". While the title downloads, the poster also
  shows a progress bar.

Not in this release: Trakt, Simkl, MDBList and Plex watchlist sync still skip
titles the library doesn't have.