Add script with "intelligent" reset

Create a new script (`JO_JOINM.BAF`), can be enabled via dialogue box.

Every test shows colored string if an error is found. And reset it if possible.
The aim is to rectify the problems without glossing over them.

examples:
```
IF
!Global("JO_JOIN_IS_TRAVELER","LOCALS",0)
Global("JO_TRAVELER_%Death_var%","GLOBAL",0)
THEN
RESPONSE #100
DisplayStringHead("^R …^-")
SetGlobal("JO_TRAVELER_%Death_var%","GLOBAL",1)
Continue()
END
```

```
IF
Global("JO_JOIN_IS_TRAVELER","LOCALS",0)
HasItem("JOMINHP1",Myself)
THEN
RESPONSE #100
DisplayStringHead("^R …^-")
EquipItemEx("JOMINHP1",1)
DestroyItem("JOMINHP1")
Continue()
END
```

The issue is about creating a new script file `JO_JOINM.BAF` for a game mod. Look at existing .BAF files in the repository to understand the syntax and structure. The script should include condition checks and actions like DisplayStringHead and SetGlobal. Test by enabling it via a dialogue box in the game to see if errors are displayed and reset correctly.

Vom Indexierungsmodell aus dem Issue-Text verfasst.