Move update calls for ServoRelayEvents and Notify up to AP_Vehicle

[peterbarker]

Biggest change here is in Sub; previously ServoRelayEvent's update was called at 3Hz, this moves it to 50 like all the other vehicles.

The estimated max time taken for the calls in the ServoRelayEvent case was different for each of the vehicles here.

Flashed this onto a PixRacer and the notify LED still works.

Also flashed onto a PixHawk and MAV_CMD_DO_REPEAT_SERVO still works.

[rmackay9]

On the dev call we decided that this PR should be put on hold for a while (1month, 2months) as we focus on resolving the issues in the 4.0 releases and complete the important functional development items for the 4.1 releases.

As a side note, when items are moved from the individual vehicle's scheduler table to the AP_Vehicle scheduler table the priority changes. In particular the AP_Vehicle's are run after the individual scheduler tables meaning that for boards that are on the edge of their CPU capabilities the LEDs may not flash at their expected rate, etc.

[khancyr]

@peterbarker would you like to rebase this. I would be good if we can merge it now !

[peterbarker]

On Mon, 25 Jan 2021, Pierre Kancir wrote:

@peterbarker would you like to rebase this. I would be good if we can merge it now !

I believe this was bounced because people were worried about scheduler task precedence - which is why I put together my "unified scheduler PR" which would let us rank all of the scheduler tasks (both common and vehicle-specific in the same list.

[peterbarker]

This has now changed to prioritise the notify library along the same lines as it was in master.