ros_compressed: Reconfigure compressed topic from request

[sfalexrog]

This P/R adds handling of the following request parameters for ros_compressed topics:

• quality: sets jpeg_quality parameter for compressed topic;
• level: sets png_level parameter for compressed topic;
• format: sets the output format (accepted values are jpeg and png).

The code in this P/R is written with the assumption that the /compressed image topic is published by compressed_image_transport and thus has the required reconfigurable parameters.

Note that this adds build-time and run-time dependencies on the dynamic_reconfigure package.

[bjsowa]

Could you rebase your commit or merge changes from ros1 branch so that the workflow triggers?