Allow source field to be deleted if dissect processor was successful

[alamzeeshan]

Is your feature request related to a problem? Please describe.
Allow source field to be deleted if dissect processor was successful

Describe the solution you'd like
Modify dissect processor to support this new configuration that allows the source to be deleted when dissect processor was successful. Something in lines of delete_source option of parse_json processor.

Example:

  processor:
    - dissect:
        map:
          message: "%{Date} %{Time} %{Log_Type}: %{Message}"
        delete_source: true

Describe alternatives you've considered (Optional)
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[alamzeeshan]

If possible, I would like to work on this feature request.

[dlvenable]

@alamzeeshan , This request sounds great. Yes, please create a PR and we'd be happy to merge. Please see the Developer Guide and let us know if you have any questions about getting started with development.