Integration Framework Refactor

[jordanvolz]

This PR makes the lolpop integration framework customizable. Previously lolpop enforced a framework of the following:

runner: 
  component: 
  pipeline: 
    component:

While this is suitable for many ML use cases, it's expected that there may be use cases where different frameworks would be desirable, so this pr makes it so a framework can be defined at runtime in your yaml file, via:

integration_framework: 
runner: 
  widget:
  component:
    widget:  
  pipeline: 
    component:
      widget: