LUA: Mission Rotation - Up to 10 selectable missions via tx switch

[robustini]

This LUA script is an evolution on the MissionSelector.LUA.
Allows you to select up to 10 missions, either while arming or in the unarmed state.
It requires that an RCx_OPTION be set to a scripting value and must match the one inside the LUA.
The scripts should be installed in the SCRIPTS folder on the MicroSD, and the mission files in the root.
The mission file called mission0.txt (the default mission) must exist and is loaded at boot, if the script does not find it it stops working.
The other mission files should have the same name with only the number changed, from 1 to 9, example mission8.txt.
To load to the next mission file just bring AUX switch from low to high for no more than three seconds, each switch loads the next mission file in numerical order.
If the next mission file numerically does not exist load the next one, at the end of the rotation it returns to load mission0.txt.
If AUX is held at high state for more than three seconds the script will restart by loading mission0.txt.
If a mission switch is attempted in AUTO flight mode, a warning "Cannot switch missions in AUTO mode" will be shown and no operation will be performed.
If try to load the script and the flight mode is AUTO you will get a message “The script cannot be loaded in AUTO mode”
Provides for sending messages under any condition, load or error.

Classic example of use, i.e. how I usually use it:

• mission0.txt is my automatic takeoff mission with home setting at a different point from arming followed by RTL, this way after manually launching my fpv plane I can put on my goggles, exit RTL and execute my flight
• mission1.txt is a full circuit mission for automatic landing, I load it if I want Ardupilot to perform an automated landing from the R side of the runway. This comes in handy, for example, if video transmission is interrupted and visibility on the ground is not optimal
• mission2.txt is like mission1.txt but executes the circuit for landing runway L the other mission files I use to perform specific automated flights
• some other mission files to run special routes

In my case if any failsafe intervenes the chosen mission is then executed.
In this way by pre scheduling the appropriate missions for the location where I fly I can afford to handle any emergencies without using GCS, simply choosing with the script the most appropriate mission, and in case changing it on the fly.
Thanks to @IamPete1 for help on intercepting the vehicle type.
Of course, suggestions, corrections and implementations are welcome!