Digital Asset Portal - usage for more than images

[ClausDW]

Is your feature request related to a problem? Please describe.
No problem - other than the option of using DAP (Digital Assets) for more than images and with specific user permissions is requested more and more.

Describe the solution you'd like
3 connected things - For Digital Assets :

1. Ability to define filetypes in the backend of DW - to handle all or more files types than is currently hard coded.
2. Ability to show a default icon for for files where we do not render a thumbnail.
3. Possibility of a list layout - rather than just gallery view - with the ability to disable thumbnails all together.

Describe alternatives you've considered
Customizing DAP.

Additional context
The idea is to be able to provide our DAP for more than just images and PDF's.
Possibly som improved permissions handling on asset folders and folders in a hierachy.