gnu: Rename qtbase to qtbase-5.

This change was automated via the following command:

$ git ls-files | xargs sed -i 's/,qtbase)/,qtbase-5)/g'
$ git ls-files | xargs sed -i 's/inherit qtbase)/inherit qtbase-5)/g'
$ git ls-files | xargs sed -i 's/package-version qtbase)/package-version qtbase-5)/g'
$ git checkout etc    # to clear some spurious changes

This is done so the qtbase package can be upgraded to version 6 in the
following commit.

gnu/packages/julia-jll.scm

@@ -1512,7 +1512,7 @@ build tree Yggdrasil.")
                ;; There's a Julia file for each platform, override them all
                (find-files "src/wrappers/" "\\.jl$")))))))
     (inputs
-     `(("qtbase" ,qtbase)))
+     `(("qtbase" ,qtbase-5)))
     (propagated-inputs
      `(("julia-jllwrappers" ,julia-jllwrappers)
        ("julia-libglvnd-jll" ,julia-libglvnd-jll)