Remove the gitconfig-mode and gitignore-mode packages

I never really used them, and they are the only ones installed from Marmalade which has a lot of
troubles (again) nowadays.

configuration.org

@@ -3445,18 +3445,6 @@ First, set up ~bibtex-completion~:
 (use-package dockerfile-mode)
 #+END_SRC
 
-** ~.gitconfig~
-
-#+BEGIN_SRC emacs-lisp
-(use-package gitconfig-mode)
-#+END_SRC
-
-** ~.gitignore~
-
-#+BEGIN_SRC emacs-lisp
-(use-package gitignore-mode)
-#+END_SRC
-
 ** ~po-mode~
 
 #+BEGIN_SRC emacs-lisp

customizations.el

@@ -95,8 +95,6 @@
      git-gutter-fringe
      git-messenger
      git-timemachine
-     gitconfig-mode
-     gitignore-mode
      gitlab-ci-mode
      gitlab-ci-mode-flycheck
      gnu-elpa-keyring-update