Add batch file to the startup files

[terrymacdonald]

Is your feature request related to a problem? Please describe.
The start programs don't allow batch files.

Describe the solution you'd like
Add .bat files to the filter for that file selection dialog in the startup program UI element.

Describe alternatives you've considered
N/A

Additional context
This will help any other users who use batch files. Typically younger users use PowerShell files (.ps1) but there are still many users who use both command files (.cmd) and batch files (.bat). This change will help those users.