Allow to load ERB variables from config file.
Generate fake secret token when precompiling.
Allow to configure settings with rake task
Add files required for packaging OpenProject with Packager.io
Use ADMIN_EMAIL to set default admin email
Move unicorn definition to main Gemfile
Add check script
Save config
Set serve_static_assets = true in case apache is not configured to serve assets.
Add unicorn config.
Set default web concurrency to 2
Use sane default sendmail options

mikel/mail uses some standard sendmail options, which we should also
use.
They can always be overridden in configuration.yml or appropriate
environment variables.

see:
https://github.com/mikel/mail/blob/1caf1b83c112ac7df2c7d95c3aa4d5604857235c/lib/mail/network/delivery_methods/sendmail.rb#L43

Conflicts:
	lib/open_project/configuration.rb
Exit if sendmail can't be found
only specify backup target once
Add route for activity details and link to comments.

Removed unnecessary include.
Use correct group and user
Use APP_GROUP instead of hardcoded openproject group
Fix order of variables in postinstall
Fix check script to use APP_USER
Allow to overwrite rails_cache_store, session_store via environment variable