Support for atomic classes orchestration

Users of PO modules should be able to deploy each 1 class per a separate orchestration action (the puppet catalog run).
For example:
* the CM graph is like: Action A -> Action B -> Action C -> ...
* the action A installs ::foo class with a set of it's init.pp class parameters as inputs
* the action B installs ::foo::bar class with a set of it's bar.pp class parameters as inputs
etc.

The user expects:
* each orchestration step should be a separate puppet catalog run containing one and only puppet class call with its class specific params.

The issue is that currently every catalog for ::foo::bar, ::foo::baz, and other classes must include the ::foo main class in order to compile w/o failures. So, there is a dependency exist for many of the PO modules and atomic orchestration steps are not possible for them.