Add ping1d depth integration in waterfall

A forum user [has suggested](https://discuss.bluerobotics.com/t/sending-node-red-data-to-mavlink-for-use-in-cockpit/22757) it could be valuable to support vehicle depth offsetting of the waterfall plot, similar to how we already have heading integration (per #48).

Not sure if the data from #109 would help with that, or if it would need to be pulled directly from MAVLink.

Start by reviewing the existing heading integration referenced in #48, then examine whether the data from #109 can provide vehicle depth or whether it must come directly from MAVLink. Done means the waterfall plot supports vehicle depth offsetting using the available ping1d data.

Written by the indexing model from the issue text.