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/lego.scm

@@ -115,7 +115,7 @@ restrictions that stem from limitations of the standard RCX firmware.")
      `(("qttools" ,qttools)))           ; for lrelease
     (inputs
      `(("mesa" ,mesa)
-       ("qtbase" ,qtbase)
+       ("qtbase" ,qtbase-5)
        ("zlib" ,zlib)))
     (arguments
      '(#:tests? #f