Add support for running under Ruby on Rails 5.0
Add support to Foreman core for running under Ruby on Rails 5.0, in addition to version 4.2 (for support of Ruby versions 2.0, 2.1 and earlier 2.2).
fixes #19050 - add Ruby on Rails 5.0 support
Adds configurable support for running on Ruby on Rails 5.0 or 4.2,
defaulting now to 5.0 on Ruby 2.3 or higher. Ruby versions with partial
or no support remain using 4.2 by default. Other points:
1. SETTINGS[:rails] is loaded pre-Rails boot, then post-boot the
majority of the SETTINGS are loaded depending on the environment.
settings.yaml.dist will allow packagers to override the default
version of Rails loaded to match their distribution.
2. rails-controller-testing, record_tag_helper replace extracted Rails
3. ParamsParser middleware is no longer loaded by default and is
deprecated, CatchJsonParseErrors is no longer order dependent.
4. quiet_assets is not supported under Rails 5, will be replaced under
ticket #18500, only affects development logging.
Refs #19050 - Use Rails 4.2 on Ruby 2.3
This unbreaks Ubuntu/xenial and Debian/stretch nightlies