Create backup option for executable

[MrClappy]

In some circumstances, application crashes, power interruptions, and/or real-time malware scanners can cause a running executable to disappear from its directory. Adding a config variable to specify a location to a backup executable can ensure the system is resilient to potential downtime as a result.

Example: EXE_BACKUP = DISABLED / FULL PATH

if %EXE% not exist
   if %EXE_BACKUP% != DISABLED
      copy %EXE_BACKUP% %CURRENT_PATH%
   else
      echo 'EXE not found and backup not enabled, exiting' > log && end