amarisoft/callbox: Add job definitions and scripts for file server

BUG=b:248293289
TEST=deploy to callbox, run curl/wget of paths at localhost:9986
  on callbox itself

Change-Id: Ie6d1764c11472209ce5ac52d40594128ce771cf8
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/4598042
Commit-Queue: Eric Caruso <ejcaruso@chromium.org>
Reviewed-by: Andrew Lassalle <andrewlassalle@chromium.org>
Tested-by: Eric Caruso <ejcaruso@chromium.org>