Ignore all custom settings and inventory files

I had multiple custom files for 2 clusters I maintain,
so I wanted to gitignore them all.

.gitignore

 # Ignore custom files created when following the README.md
-/ansible/group_vars/cluster/settings.yml
-/ansible/inventory.yml
+!ansible/group_vars/cluster/settings.yml.example
+/ansible/group_vars/cluster/settings*
+!/ansible/inventory.yml.example
+/ansible/inventory*
 
 # Ignore files created by ansible-playbook
 *.retry