Is your feature request related to a problem? Please describe.

Data Prepper added the @Experimental annotation in 2.11. Presently, all experimental plugins are enabled or not.

I'd like to enable specific experimental plugins.

Describe the solution you'd like

Add this configuration:

experimental:
  enabled:
    source:
      - rss
      - neptune
    processor:
      - ml_inference

Describe alternatives you've considered (Optional)
N/A

Additional context

Original issue for experimental plugins: #2695