use_ping_payload for acomms_driver_node and modem_sim_node.

significant updates to acomms_driver_node dynamic reconfigure (currently historic behavior is maintained).

TODO: refactor utility methods into a single location and standardize use across the package.

TODO: do we want to update dynamic reconfigure when modem params are updated out of band?

TODO: track nodes that use the modem_src_id query service and track down the implications of the modem_src_id changing after launch and if there is even a way for nodes that depend on that info to handle that change correctly..