Add file extension filter to UDInput file type

[timd19]

Is your Enhancement request related to a problem? Please describe

Ability to filter file extension (see URL below)

https://forums.universaldashboard.io/t/file-upload-howto/493/11?u=mylabonline

Describe the solution you'd like

Maybe a param (-AcceptFileExtensions) then whatever extension you want to filter in the browser window (".gif,.jpg,.jpeg,.png,.doc,.docx")

Describe how this would improve your Universal Dashboard Quality of Life

Please help us understand how this would improve your usage of universal dashboard and/or what new capabilities this enhancement would provide you with.

Describe alternatives you've considered

A clear and concise description of any alternative solutions or Enhancements you've considered.

Additional context

Add any other context or screenshots about the Enhancement request here.

[Joe-Palmer]

This would be a great feature!