Telemetry RSSI

Plan: Add support for SET_CAMERA_MODE command

* 'master' of https://github.com/mavlink/qgroundcontrol: (95 commits)
  Only mobile limits line length
  Drag support
  Fix indicator
  Correct background color
  Fix parameter mapping
  No max altitude
  Fixed support for closing all guided dialogs
  Core plugin can override Value Widgets default settings
  Add flightTime to Vehicle FactGroup
  Add support for valueTypeElapsedTimeInSeconds
  Max default mission altitude is 400ft
  Mention voiding warranty in show advanced ui confirmation
  Still trying to fix merge
  Fix merge
  Support load/save/default of NaN for param
  Allow core plugin to disable multi-vehicle
  Stop trying to pull from vehicle
  Support load/save/default of NaN for param
  Add support for FMUv4PRO and FMUv5 boards
  Remove WIP
  ...

ArduPilot Camera Setup:  Fix parameter mapping

Only mobile limits line length for fly view trajectory lines

Rally point drag

Mission settings: No max altitude

Fly-Guided: Fixed support for closing all guided dialogs

Flight timer

Also added Vehicle.flightTime to default setup

Fixes

Allow core plugin to disable multi-vehicle support

Plan: Default hover/cruise speed, stop trying to pull from vehicle

Plan: Support load/save/default of NaN for command param

Just use settings defaults

Add support for FMUv4PRO and FMUv5 boards

This adds support for the full-sized FMUv4PRO design and the FMUv5 STM32F7 based generation.

Land abort sliders pop up based on new mavlink landing state

Fixed Wing Landing pattern