gnu: Remove QuiteRSS due to dependency on QtWebKit.

According to the upstream developers, "Unfortunately, qtwebkit won't
work without it. Everything is very much tied to qtwebkit."

https://github.com/QuiteRSS/quiterss/issues/1470

Additionally, there is no work being done to remove this dependency:

https://github.com/QuiteRSS/quiterss/issues/909

Other distros are removing this package as part of the effort to remove
QtWebKit:

https://bugzilla.redhat.com/show_bug.cgi?id=1872819
https://bugs.gentoo.org/687840

See <https://issues.guix.gnu.org/53289> for more information about this change.

* gnu/packages/syndication.scm (quiterss): Remove variable.

gnu/packages/syndication.scm

@@ -511,56 +511,6 @@ (define-public rawdog
 formats, including all versions of RSS and Atom.")
     (license license:gpl2+)))
 
-(define-public quiterss
-  (package
-    (name "quiterss")
-    (version "0.19.4")
-    (source (origin
-              (method git-fetch)
-              (uri (git-reference
-                    (url "https://github.com/QuiteRSS/quiterss")
-                    (commit version)))
-              (file-name (git-file-name name version))
-              (sha256
-               (base32
-                "1cgvl67vhn5y7bj5gbjbgk26bhb0196bgrgsp3r5fmrislarj8s6"))
-              (modules '((guix build utils)))
-              (snippet
-               '(begin
-                  (substitute* (find-files "." "\\.cpp$")
-                    ;; Disable Google Analytics spyware by default,
-                    ;; removing completely is not trivial.
-                    (("settings\\.value\\(\"Settings/statisticsEnabled2\", true\\)")
-                     "settings.value(\"Settings/statisticsEnabled2\", false)")
-                    ;; Disable update check spyware by default, otherwise runs
-                    ;; at every startup, nasty. Not needed on GNU Guix as a
-                    ;; feature either way.
-                    (("settings\\.value\\(\"Settings/updateCheckEnabled\", true\\)")
-                     "settings.value(\"Settings/updateCheckEnabled\", false)"))
-                  #t))))
-    (build-system qt-build-system)
-    (arguments
-     `(#:tests? #f ;; no test suite
-       #:phases
-       (modify-phases %standard-phases
-         (replace 'configure
-           (lambda* (#:key inputs outputs #:allow-other-keys)
-             (invoke "qmake" "CONFIG+=release"
-                     (string-append "PREFIX="
-                                    (assoc-ref outputs "out"))
-                     (string-append "QMAKE_LRELEASE="
-                                    (assoc-ref inputs "qttools")
-                                    "/bin/lrelease")))))))
-    (native-inputs
-     (list pkg-config qttools))
-    (inputs
-     (list qtwebkit qtbase-5 qtmultimedia phonon sqlite))
-    (home-page "https://quiterss.org/")
-    (synopsis "RSS/Atom news feeds reader written on Qt/C++")
-    (description "QuiteRSS is an RSS/Atom news feeds reader written on Qt/C++
-that aims to be quite fast and comfortable to its user.")
-    (license license:gpl3+)))
-
 (define-public gfeeds
   (package
     (name "gfeeds")