Implement download_file in widget driver (#12931)

* Implement download_file in widget driver

Signed-off-by: Michael Weimann <michael.weimann@nordeck.net>

* Fix test URIs

Signed-off-by: Michael Weimann <michael.weimann@nordeck.net>

* Use download-file branch as widget-api source

Signed-off-by: Michael Weimann <michael.weimann@nordeck.net>

* bump matrix-widget-api to 1.9.0

Signed-off-by: Kim Brose <kim.brose@nordeck.net>

* prettier

Signed-off-by: Kim Brose <kim.brose@nordeck.net>

---------

Signed-off-by: Michael Weimann <michael.weimann@nordeck.net>
Signed-off-by: Kim Brose <kim.brose@nordeck.net>
Co-authored-by: Kim Brose <kim.brose@nordeck.net>