caddy: disable fail_timeout by default

gitlab has 502 errors quite frequently (workhorse / unicorn problems?) and caching the failure is not helpful, so this should probably stay disabled.

caddy: update for latest version

proxy_header has been deprecated

Fixes https://gitlab.com/gitlab-org/gitlab-recipes/issues/56

* fix a typo
* installing gitlab-shell needs repositories path
* bump to current versions, tested/installed on freeBSD 10.3 p7

Update docs for installing GitLab on FreeBSD 10.3

Update CentOS6 install instructions for GitLab 8.9

Added caddy web-server recipe

Adjust some of the DB stuff

Replicated on Fresh FreeBSD 10 install

Turns off NoEscape flag. Adapted from https://gitlab.com/gitlab-org/gitlab-ce/issues/3163

Comment to change config files to use full path

gitlab/config and gitlab-shell/config had symbolic links (/home/*), but they needed to be full paths (/usr/home/*) for pushing from command line and adding files from the web browser.

(Fix found at https://github.com/gitlabhq/gitlabhq/issues/8703 and worked or me.)

systemd: remove unused (for 8.2.x onwards) files.

systemd: update gitlab-workhorse for 8.3.x.

systemd: add unit for gitlab-workhorse.

Please note that this deprecates the gitlab-git-http-server used for
8.0-8.1. Gitlab Workhorse is used from 8.2 and hopefully onwards.

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/1919