If Facts are referenced from FactPanelController, we need to reference
count the AutoPilotPlugin such that it doesn’t get destroyed until
after the FactPanelController is destroyed.

Otherwise they end up referencing deleted Facts on link disconnect

Was causing unnecessary read re-requests to get sent out

QGCUASParamManager and friends are replaced by FactSystem

More consistent with Qml usage pattern

Also many LinkManager API changes to further isolate all link
management inside LinkManager.

If it doesn’t exist it will be prefilled with all registered categories
set to false

FactTextField, when setting the value from its "text" field, was converting the value to string. This was causing (QML JavaScript) code that uses the value for computation to stop working once the user changed the value.

Also changed to qWarning