Don't create os-settings.conf in install step

For Server < 2.0, the value for ruby-load-path in os-settings.conf depended on the operating system and where ruby was installed etc. This meant that we generated this conf file during the install step of packaging (https://github.com/puppetlabs/puppet-server/blob/master/resources/ext/ezbake.conf#L22-L24 and https://github.com/puppetlabs/puppet-server/blob/master/resources/ext/ezbake.conf#L36-L38) and that we have to do some hackery in the acceptance tests (https://github.com/puppetlabs/puppet-server/blob/master/acceptance/lib/helper.rb#L154-L186) to lay this down when using beaker.

For AIO, the ruby-libdir will always be the same thing no matter the platform, so we can lay os-settings.conf down in a regular config file and remove all of this stuff.