Refactor the action layer for modules to load the actions directly not just names

[lsilvs]

Expected behavior

Modify the implementation with these guidelines:

1. Remove channel.action completely
2. User can only define actions for a module in the module specification as an object, where keys of object are action names.
3. Load those actions object in the controller properly (already have some implementation but need refactoring)
4. The rest of the flow works exactly the same

Actual behavior

In current implementation the flow for actions is as below:

1. At the time of module initialization, it provide array of actions (string names) that module supports.
2. Controller pass the channel object while loading the module
3. Module can actually define the action by using channel.action method during module loading async load method.

This flow does makes some ambiguity and difficult user flow. User may define the actions in different files, but forget to mention those in the module specification and vice versa. And its also difficult to find where the actions for particular modules are listed.

Which version(s) does this affect? (Environment, OS, etc...)

1.6.0