Update kfp component files to include optional parameter

[akchinSTC]

• Update the kfp component definitions to align with best practices
  and include descriptions and source license information
• Set directory as source when reading local custom components
• Remove runtime type from reader abstract method

What changes were proposed in this pull request?

How was this pull request tested?

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[ptitzler]

Could we add a comment at the beginning of each example component file:

• Since Elyra re-uses existing components that were published by somebody else, we should document the raw URL where the YAML file originally came from , e.g.

  # Component source location: https://...
  

• Often there is not enough information in the specification for the user to make an informed decision about valid values. If one exists, we should reference a web page (if applicable) that contains more details. For example, https://github.com/kubeflow/pipelines/blob/master/components/kubeflow/kfserving/README.md

  # Component details: https://
  

[lresende]

@akchinSTC Could you please update the license and list the origin + license of these component files

[lresende]

@akchinSTC @kiersten-stokes Could you please resolve conflicts.

[kiersten-stokes]

I think the linting issue below is the only outstanding thing for this PR (I say as if I didn't introduce the problem...)

[lresende]

We need to make the registry aware of the additional location where components are located either by convention and/or by explicitly adding things on the registry JSON with the proper type and not let a reader calculate the location based on the type of the runtime, because then that reader looses its flexibility

[kiersten-stokes]

LGTM! Tested an example for each runtime and each succeeded

[lresende]

I am not sure if for file-based directory of components we need to list one by one in the registry, but for this PR I guess it's ok to avoid delays, but we will need to revisit this in the future.