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

unify Apache config files, fix missing RewriteCond lines for gitlab-workhorse in non-omnibus configs
(8 conf files with almost the same content easily run out of sync)

When getting an archive from the API, the ID can be NAMESPACE/PROJECT_NAME
http://gitlab.mycompany.com/api/v3/projects/foo%2Fbar/repository/archive.zip?sha=87a5db5ea887763fa3a31a5471b512ff1596d9b8

The Apache option "NE" avoids double encoding of the %2F

Revamp apache config files and README

Conflicts:
	web-server/apache/gitlab-8.0-apache2.2.conf
	web-server/apache/gitlab-8.0-ssl-apache2.2.conf

Updated configuration for Gitlab 8.x and Apache Httpd 2.2.x. after rebase and integration of b8290a5c commit.

Fix mailroom wget command in systemd README

Aligned them to nginx config in gitlab-ce to make downloads work.

Add mailroom service

add incomming email queue

Issue #268 Updated Apache config for not to encode %2F double