Cherry pick virtual joystick fix from Stable

Updated mavlink forwarding implementation to forward all mavlink messages received on all channels onto a single UDP port. A new mavlink forwarding UDP link is created if forwarding is enabled. The mavlink settings page now has a Fact checkbox for enabling forwarding and a fact text field for specifying the host name.

Modified support for multiple first run pages. Added first run for offline vehicle settings.

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Grouped logging options within General Settings

On desktop (Ethernet connection), the ground unit pushes UDP directly, which makes the use of an actual "Link" not possible. Instead, I've moved all of Taisync support to a "manager" owned by QGCToolbox.
Added a Taisync settings with some basics already wired and running.

ArduPilot option to not start mavlink streams

Show the link indicator in the tool bar if two or more links are connected and at least one of them is a high latency link.
Show in the link indicator if a link is inactive.

This setting enables/disables the LinkIndicator toolbar in which the primary link can be chosen.

Automated preflight checklist: Initial commit. Note that this requires an autopilot firmware that writes the respective health flags in the SYS_STATUS mavlink message

All settings wired and persistent
Cleanup non Airmap builds

Added AirMap settings (SettingsGroup)
Added AirMap settings block to General Settings
Create macros to deal with the tedious repetitions within SettingsGroup
Removed old, hacked in setting for AirMapKey
Remove a few of the tons of build warnings

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>