Installation/update improvements

[XVilka]

• Provide configs all with .example prefix and add .yml in .gitignore
• Allow to use git pull; git checkout for updating

See good example how this done in GitLab https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/update/7.7-to-7.8.md

[scouttyg]

👍 This makes sense to me, I'll add this in this weekend