fw_att_control delete dead code and minor cleanup

[dagar]

The FW coordinated turn parameters aren't used anymore so I deleted them in both the fw_att_control side and ecl. I also split the large single cpp file and named it to match the class.

ECL side: PX4/PX4-ECL#319

[dagar]

The only real change here is deleting the unused yaw coordination parameters, the rest is the single massive file, and trivial cleanup. @bresch @sanderux could you do a quick review?

[dagar]

TODO: readd ECL side PX4/PX4-ECL@b0300b9

[mrpollo]

please test @PX4TestFlights after @dagar rebase

[dagar]

Let's get #7773 in first, then I'll rebase.

[santiago3dr]

flight with a phantom flying wing running a pixhawk mini (V3)
https://logs.px4.io/plot_app?log=d5fafeac-9158-47b7-92c7-3e9d75a2f6f2
manual input non responsive in stabilized or altitude; rtl took a nose dive; had to retake manual control

compared to master on the same platform:
https://logs.px4.io/plot_app?log=3ba15b95-8a61-4f0f-a224-3539d706ed89

[dagar]

Thanks, will review the log in detail.
Did you build this branch yourself? The ecl commit is now gone so I'm wondering if something is was screwed up there. This was tested successfully in SITL.