[deviantart] remove prefer-public option

All API requests now always use a public token and only switch to
a private token for pagination results if `refresh-token` is set
and less deviations than requested were returned.

docs/configuration.rst

@@ -333,23 +333,6 @@ Description Download full-sized original images if available.
 =========== =====
 
 
-extractor.deviantart.prefer-public
-----------------------------------
-=========== =====
-Type        ``bool``
-Default     ``false``
-Description Call API endpoints with a public access token first
-            and only switch to a private access token if deviations are missing
-            (i.e. they are only visible to logged in users).
-
-            This option only has an effect when using a `refresh token`__
-            and tries to minimize the amount of API calls with private access
-            tokens, as they have a much lower rate limit than public ones.
-
-            __ extractor.deviantart.refresh-token_
-=========== =====
-
-
 extractor.deviantart.refresh-token
 ----------------------------------
 =========== =====

docs/gallery-dl.conf

@@ -17,7 +17,6 @@
         "deviantart":
         {
             "refresh-token": null,
-            "prefer-public": false,
             "flat": true,
             "journals": "html",
             "mature": true,