Reword common stanzas in the cabal file generated by cabal init

Following #11231, this commit reworks the common stanzas present in the
cabal file generated by `cabal init`.

Author: Kleidukos

cabal-install/src/Distribution/Client/Init/FileCreators.hs

@@ -73,14 +73,17 @@ writeProject (ProjectSettings opts pkgDesc libTarget exeTarget testTarget)
 
       let pkgFields = mkPkgDescription opts pkgDesc
           commonStanza = mkCommonStanza opts
+          extensionsStanza = mkExtensionsStanza opts
+          ghcOptionsStanza = mkGhcOptionsStanza opts
+          rtsOptionsStanza = mkRtsOptionsStanza opts
 
       libStanza <- prepareLibTarget opts libTarget
       exeStanza <- prepareExeTarget opts exeTarget
       testStanza <- prepareTestTarget opts testTarget
 
       (reusedCabal, cabalContents) <-
         writeCabalFile opts $
-          pkgFields ++ [commonStanza, libStanza, exeStanza, testStanza]
+          pkgFields ++ [extensionsStanza, ghcOptionsStanza, rtsOptionsStanza, commonStanza, libStanza, exeStanza, testStanza]
 
       when (null $ _pkgSynopsis pkgDesc) $
         message opts T.Warning "No synopsis given. You should edit the .cabal file and add one."