* If new Survey is set to altitude fixed value then use mission default
altitude
* If the user applies a new altitude to the entire mission change
surveys to fixed altitude and apply altitude

This way if the user switches away from manual the altitude is preserved

This reverts commit ac73682a.

This reverts commit 6620f803.

Previously, a completed file upload lead to this assert:
    Q_ASSERT(!_ackTimer.isActive());
because _closeUploadSeesion() was called twice, thus activating the timer
twice.

Plus other ui tweaks

Hide "Save Path" as it breaks the UI in General Settings.

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